Graft copolymers of vascular plants, method of making same and uses therefore

A graft copolymer of a vascular plant having a biologically produced part that is the plant or a component thereof and at least one sidechain, Sc, having randomly repeat unit, R.sub.ru, wherein R.sub.ru are formed by the polymerization of at least one substituted ethene polymerable by free radical polymerization. The sidechain repeat unit, R.sup.ru, has the structure ##STR1## such that the side groups, R.sub.i where i=1 to 4, on the sidechain are selected from the group of alkanes, alkenes, amides, alcohols, alkoxides, aromatics, cycloalkanes, esters, halogens, hydrogen, phenols, and nitrile groups and such groups further substituted with one or more groups. The side groups on the sidechain may vary from one repeat unit to another. The number of sidechains on the woody plant fragment can vary from 1 to 500 and the number of repeat units in each sidechain can vary from 1 to 500,000. The invention provides a vascular plant or component thereof, chemically bound to a polymerized chain of repeat units from ethene monomers which possess the desirable properties of a thermoplastic, the desirable properties of a macromolecular surfactant, the desirable properties of a thermoplastic which degrades completely in the environment, the desirable properties of a controlled release agent, and the desirable features of a wood-reinforced, thermoplastic composite.

FIELD OF THE INVENTION 
The present invention relates to graff copolymers of vascular plants, 
methods of making the same, and uses therefore. 
BACKGROUND OF THE INVENTION 
Thermoset and thermoplastic materials have provided significant performance 
advantages because of their relatively high strength compared to weight. 
This allows thermoplastic materials to be used in devices ranging from 
consumer items to complex industrial equipment. Pure thermosets and 
thermoplastics have a homogeneous internal composition and have minimal or 
no activity at a surface or phase boundary. The materials are also prone 
to "creep" as an applied load or the solid's own weight cause the solid to 
deform with time. Attempting to form a composite by mixing a vascular 
plant part and a plastic made from an ethane monomer produces a material 
in which the two components clump into large, separate phases to produce a 
weakened, unstructured solid with no surface activity, no wetting of woody 
interfaces, decreased binding strength even in the two phase solid, and 
degradation of the plant phase alone under attack by microorganisms. 
SUMMARY OF THE INVENTION 
The invention provides new compositions of matter in which a vascular 
plant, its pans, or its structural constituents are converted into 
thermoplastics, surface active agents, and composites. The material is a 
thermoplastic if lignin is used as the backbone. This is a hard, strong, 
thermoplastic that can be molded, cast, and extruded into parts, 
equipment, and consumer items; occupies interfaces between a woody phase 
and a plastic phase; couples these phases together to increase binding 
strength; has both backbone and sidechain degrade under attack by 
microorganisms; forms structured heterogeneous solids; forms insulating 
degradable foams when blown into a porous cellular foam; and can release 
groups attached to backbone or sidechain as degradation fragments useful 
as medications, reagents or initiators in controlled release processes. 
The material is a wood-reinforced, hydrophobic composite with limited 
creep, increased tensile strength compared to the plastic made from the 
ethene monomer, firm binding between wood arid plastic and thermoplastic 
flow properties if the backbone is any part of a vascular plant or grass. 
The invention comprises a grafted part of a vascular plant or its 
structural constituents as well as grafted products thereof. A vascular 
plant is any of the shrubs, trees, herbs, grasses, ferns, or flowers that 
make up the flora. The structural constituents of a vascular plant are the 
three polymers that plants use to construct themselves. These structural 
constituents are any mixtures of cellulose, hemicellulose, and lignin that 
contain at least 0.01 weight percent lignin. These structural constituents 
may be blended together in a mixture or they may be chemically linked to 
one another up to and including the point where the connected compounds 
become part or all of a vascular plant. Grafted to this central plant part 
network is at least one grafted sidechain having randomly repeating units 
R.sub.ru wherein R.sub.ru is formed by the polymerization of at least one 
substituted ethene by free radical polymerization, and the side groups on 
R.sub.ru, R.sub.i where i=1 to 4, are selected from the group of acids, 
alcohols, alkanes, alkenes, alkoxides, amides, aromatics, cycloalkanes, 
esters, halogens, hydrogen, nitrile, and phenol groups and such groups 
further substituted with one or more groups. 
The invention provides a vascular plant or its structural constituents 
chemically bound to a polymerized chain of repeat units from ethene 
monomers which possess the desirable properties of a thermoplastic: 
strength, impact resistance, and deformability at higher temperature; the 
desirable properties of a macromolecular surfactant: populating 
interfaces, wetting wood until it is hydrophobic, and forming internally 
structured solids; the desirable proparties of a thermoplastic which 
degrades completely in the environment; the desirable properties of a 
controlled release agent: emission of pharmaceuticals, reagents and 
initiators as degradation fragments over time; and the desirable features 
of a wood-reinforced, thermoplastic composite: reduced creep, increased 
strength, and capacity to deform and shape with heat. 
In a preferred embodiment, the invention provides a substance produced from 
all, part, or a mixture of the structural constituents of a vascular 
plant. Vascular plants, are the members of the plant kingdom with an 
internal organization of tubes, xylem and phloem channels, made out of 
three types of cells, parenchyma, collenchyma, or sclerenchyma cells. A 
part of the plant is any contiguous piece of a root, shoot, or leaf of the 
plant. A mixture of the structural constituents of the plant contains 
hemicellulose, and lignin, possibly contaminated with the inert "mineral" 
portion of the plant: starch, lipid, silica bodies, silica stegmata, 
protein bodies, and mucilage. 
The vascular plant, its part, or a mixture of the plant's structural 
constituents has a cellulose content of 0 to 99.9 weight percent, a 
hemicellulose content of 0 to 90 percent, a lignin content of 0.01 to 100 
weight percent, and a mineral content of 0 to 60 weight percent. These 
chemically distinct parts of the vascular plant may be bound into the 
naturally-occurring structures of a vascular plant; bark; phloem; xylem; 
or cambium; parenchyma, collenchyma, or sclerenchyma cells; or can be 
mixtures of cellulose, hemicellulose, lignin, and minerals, chemically 
distinct molecules that can be separated from the vascular plant. All 
vascular plants contain polymeric, alkylaromatic compounds made from 
coumaryl, coniferyl, and synapyl alcohol. Attached to these polymeric, 
alkylaromatic compounds in the plant fragment by carbon-carbon bond is at 
least one sidechain, Sc, having randomly repeating units, R.sub.ru, 
wherein R.sub.ru are formed by the polymerization of at least one 
substituted ethene polymerizable by free radical polymerization. The 
sidechain repeat unit, R.sub.ru, has the structure 
##STR2## 
such that the side groups, R.sub.i where i=1 to 4, on the sidechain are 
selected from the group of alkanes, alkenes, amides, alcohols, alkoxides, 
aromatics, cycloalkanes, esters, halogens, hydrogen, phenols, and nitrile 
groups and such groups further substituted with one or more groups. The 
side groups on the sidechain may vary from one repeat unit to another. The 
number of sidechains on the woody plant fragment can vary from 1 to 500 
and the number of repeat units in each sidechain can vary from 1 to 
500,000. 
The present invention also provides a process for making a grafted 
copolymer of a vascular plant at high yield which possesses the desirable 
properties of a thermoplastic, wetting agent, coupling agent, composite, 
microdomain solid, and compostable plastic. 
This new method circumvents the synthesis failures which are encountered 
when 2-propenamide is replaced by a substituted ethene with a different 
dipole moment and sharply reduced water-solubility. To react ethane 
monomers with dipole moments below 1.2 or above 1.8 and water solubilities 
of less than 5.0 g of monomer per 100 g of water at 30.degree. C. with a 
vascular plant part to produce grafted product requires continuous 
stirring during the reaction, preferably at a controlled stirring rate. 
The method thus allows synthesis of materials impossible to prepare by 
known methods. 
The deficiencies of prior methods are overcome by the invention using the 
thermoset or thermoplastic materials made from two components, a backbone 
and sidechain. A molecular backbone grafted with a sidechain has now been 
shown to make a surface active agent which can form heterogeneous solids 
and populate an interface. Vascular plants are composites themselves with 
their structure formed by bonds between aggregates of different molecules. 
This composite backbone, grafted with a thermoplastic sidechain, has now 
been shown to create a fiber-reinforced, thermoplastic composite. Such 
composites are only possible by the method of the invention which 
chemically connects backbone and sidechain, a particularly difficult 
process if the backbone is an inconsistent and varied material like 
vascular plants, wood, and lignin.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
In accordance with the present invention, there is provided a high 
molecular weight grafted material. The invention comprises a grafted 
vascular plant, plant part, or structural constituent mixture which is at 
least one of the group listed in Table 2B, the grafted portion having at 
least 0.01 weight percent lignin, a cellulose content of 0 to 99.9 weight 
percent, a hemicellulose content of 0 to 90 weight percent, and a combined 
starch, lipid, crystal, silica bodies, silica stegmata, protein bodies, 
and mucilage content of 0 to 60 weight percent, such that to this central 
plant part network is grafted at least one sidechain having randomly 
repeating units R.sub.ru wherein R.sub.ru is formed by the polymerization 
of at least one substituted ethene by free radical polymerization, and the 
side groups on R.sub.ru, R.sub.i where i=1 to 4, are selected from the 
group of acids, alcohols, alkanes, alkenes, alkoxides, amides, aromatics, 
cycloalkanes, esters, halogens, hydrogen, nitrile, and phenol groups and 
such groups further substituted with one or more groups. 
The invention provides a lignin, grass, bark, leaf, twig, root, seed, wood, 
wood fiber, or wood pulp, chemically bound to a polymerized chain of 
repeat units from ethene monomers which possess the desirable properties 
of a thermoplastic: strength, impact resistance, and deformability at 
higher temperature; the desirable properties of a macromolecular 
surfactant: populating interfaces, wetting wood until it is hydrophobic, 
and forming internally structured solids; the desirable properties of a 
thermoplastic which degrades completely in the environment; the desirable 
properties of a controlled release agent: emission of pharmaceuticals, 
reagents and initiators as degradation fragments over time; and the 
desirable features of a wood-reinforced, thermoplastic composite: reduced 
creep, increased strength, and capacity to deform and shape with heat. 
In a preferred embodiment, the invention provides a substance produced from 
all, part, or a mixture of the structural chemicals, of a vascular plant. 
The vascular plant or a part of it can be wood; wood pulp; wood fiber; 
wood filament; wood veneer; xylem; bark; twigs; roots; shoots; leaves; 
seeds; phloem; cambium; parenchyma, collenchyma, or sclerenchyma cells; 
lignin; or structured plant parts from any grass, softwood, or hardwood. 
The mixture of the structural chemicals of the plant can be cellulose, 
hemicellulose, and lignin, contaminated with minerals: starch, lipid, 
crystal, silica bodies, silica stegmata, protein bodies, and mucilage. 
The vascular plant, its part, or a mixture of the plant's structural 
constituents has a cellulose content of 0 to 99.9 weight percent, a 
hemicellulose content of 0 to 90 percent, a lignin content of 0.01 to 100 
weight percent, and a mineral content of 0 to 0 weight percent. These 
chemically distinct parts of the vascular plant may be bound into the 
naturally-occurring structures of a vascular plant; bark; phloem; xylem; 
cambium; or parenchyma, collenchyma, or sclerenchyma cells; or can be 
mixtures of cellulose, hemicellulose, lignin, and minerals, chemically 
distinct molecules that can be separated from the vascular plant. Attached 
to polymede, alkylaromatic compounds in the plant fragment by 
carbon-carbon bond is at least one sidechain, Sc, having randomly 
repeating units, R.sub.ru, wherein the sidechain repeat unit, R.sub.ru, 
has the structure 
##STR3## 
such that the side groups, R.sub.i where i=1 to 4, on the sidechain are 
selected from the group of alkanes, alkenes, amides, alcohols, alkoxides, 
aromatics, cycloalkanes, esters, halogens, hydrogen, phenols, and nitrile 
groups and such groups further substituted with one or more groups. In one 
preferred embodiment of the invention, these side groups, when detached 
from the backbone by environmental degradation, become pharmaceuticals, 
reagents or initiators. The side groups on the sidechain may vary from one 
repeat unit to another and when they do the sidechain is a random 
copolymer. Common monomers represented by this structure are: 
1-chloroethene; 1,1,2,2-tetrafluoroethene; 1 -phenylethene; 1 
-(4-bromophenyl)ethene; 1-(4-chlorophenyl)ethene; 1,n-diethenylbenzene, 
where n=2, 3, or 4; 1,3-butadiene; 2-methyl-1,3-butadiene; 2-propene 
nitrile; 1,1-dichloroethene; N,N-bis(2-propenamido)methane; 
1-methyl-1-phenylethene; 2-chloro-1,3-butadiene; 2-oxo-3-oxypent-4-ene; 
2-oxy-3-oxopent-4-ene; 4-methyl-2-oxy-3-oxopent-4-ene; propene; or ethene. 
The number of sidechains on the woody plant fragment can vary from 1 to 
500 and the number of repeat units in each sidechain can vary from 1 to 
500,000. For example, when using a vascular plant or plant part in 
accordance with the present invention, a graft product of the formula of 
FIG. 1 is produced. 
When using a mixture of plant compounds in accordance with the present 
invention, a graff product of the formula of FIG. 2 is produced. 
The present invention also provides a process for making a grafted vascular 
plant, plant part, or structural chemical mixture at high yield which 
possesses the desirable properties of a thermoplastic, wetting agent, 
coupling agent, composite, microdomain solid, and compostable plastic. 
This new method circumvents the synthesis failures which are encountered 
when polar, water-soluble monomers are replaced by another substituted 
ethene with a different dipole moment and sharply reduced water 
solubility. To react ethene monomers with dipole moments below 1.2 or 
above 1.8 and water solubilities of less than 5.0 g of monomer per 100 g 
of water at 30.degree. C. with a vascular plant part to produce grafted 
product requires continuous stirring during the reaction, preferably at a 
controlled stirring rate. Such stirring is critical and in the absence of 
stirring, a grafted product simply cannot be produced. 
The classification of Kingdom Plantae in biology is stable and universally 
accepted. The nomenclature of Bold, Alexopoulos, and Delovoryas; H. C. 
Bold, C. J. Alexopoulos, T. Delevoryas, Morphology of Plants and Fungi, 
1980, Harper and Row, New York; will be used to identify vascular plants, 
the Tracheophytes, as those that have vascular tissues specialized for 
conduction of water. This group of plants includes vascular cryptogams; 
divisions Psilotophyta, Microphyliophyta, Arthrophyta, and Pterophyta; and 
seed plants, the Spermatophytes; divisions Trimerophytophyta, 
Progymnospermophyta, Cycadophyta, Coniferophyta, Anthophyta, Ginkgophyta, 
and Gnetophyta. The seed plants developed the "modern" structures: wood, 
bark, and seeds. Viewed by their external organization, vascular plants 
consist of three parts: root, shoot, and leaf. Viewed by their internal 
structure, vascular plants consist of three fundamental types of cells: 
Parenchyma, with thin walls; Collenchyma, with irregularly thickened 
walls; and Sclerenchyma, with very thick, strong walls. The body of the 
plant is covered with an epidermus, often containing glands, hairs, and 
stomata. Interior to this is the cortex, the bulk of which is made up of 
parenchyma cells. Inside the cortex is the stele, vascular tissues 
consisting of xylem or phloem structures. Portions of this invention show 
how the new thermoplastic coupling agents can be applied to wood, wood 
pulp, or wood fiber. Wood is defined as the hard fibrous substance, 
basically xylem, that makes up the greater part of the stems and branches 
of trees or shrubs. It is found beneath the bark and is also found to a 
limited extent in herbaceous plants. 
Chemically, the plant and its parts are made up of starch; lipid; druses, 
raphides, and styloids crystals; silica bodies and stegmata; protein 
bodies; mucilages; cellulose; hemicellulose; and lignin. These structures 
and molecules are described in Plant Anatomy, James D. Mauseth, 1988, 
Benjamin Cumming's Publishing, Menlo Park, Calif., ISBN 0-8053-4570-1. 
These chemically distinguishable plant compounds exist both as mixtures 
and as chemically bound, larger molecules within the plant or its parts. 
The materials can be grafted as an aggregate in a plant or its parts or as 
mixtures of the separate structural plant compounds blended together. 
Lignin [8068-00-6] is derived from woody plants. Common subclasses of 
lignin are: chlorinated lignin, [8068-02-8]; 1,n-dioxacyclohexane 
acidolysis lignin, [8068-03-9]; Holmberg lignin, [8068-07-3]; hydrochloric 
acid lignin, [8068-11-9; kraft lignin, [8068-05-1]or [8068-06-2]; soda 
lignin, [8068-05-1] or [8068-01-7]; sulfite lignin, [8062-15-5]; and 
sulfuric acid lignin, [8068-04-0]. Lignins are produced by all vascular 
plants from coumaryl, coniferyl, and sinapyl alcohol. 
The preparation of this copolymer is accomplished, in general, under 
oxygen-free conditions by adding a redox initiator; a halide salt, 
chloride salt preferred; and an ethene monomer to a vascular plant, plant 
part, or mixture of structural plant constituents dispersed in a suitable 
solvent and allowing time for graft polymerization to occur. 
Example A 
This example, Example A, provides the basic, non-quantitative method. 
Significant variation in reaction mixture composition and preparation 
procedure are possible as will be illustrated in subsequent examples which 
follow Example A. 
The basic method for the preparation of a graff copolymer of a vascular 
plant, plant part, or mixture of plant compounds in dimethylsulfoxide, 
1,4-dioxacyclohexane, or dimethyl formamide for a sample composed of 
between 0.1 and 35 weight percent plant material; 0.1 and 40.0 weight 
percent ethene monomer; 0.3 to 15.3 weight percent metal halide salt, 
chloride salt preferred; and 25 to 97 weight percent solvent; are 
presented here. 
The method generally comprises: 
a) An aliquot of one-half to all of the purified solvent is placed in a 
sealable reaction vessel. Some suitable solvents for the reaction are 
listed in Table 1. 
b) Finely ground anhydrous halide salt, chloride salt preferred, are added 
to the solvent. Typical salts are listed in Table 2A. 
c) The vascular plant, plant part, or mixture of plant compounds is added 
to the solvent and the mixture is agitated to disperse the plant 
component. Typical vascular plant parts are listed in Table 2B. In a 
process to react large parts of the plant, such as 2 to 3 meter wide 
veneer sheets, the introduction of the large plant part will usually be 
delayed until after step f. The plant part will then be run through or 
bathed in the reaction mixture of step f within an oxygen-free zone. 
d) The mixture is stirred for about 20 minutes to dissolve the solids while 
being bubbled with nitrogen. 
e) After 10 minutes of nitrogen saturation, a hydroperoxide such as 
hydrogen peroxide or 2-hydroperoxy-1,4-dioxacyclohexane is added to the 
reaction mixture. A selection of suitable hydroperoxides for the graff 
copolymerization are shown in Table 3. 
f) An ethene monomer polymerizable by free radical reaction is added to the 
reaction vessel under a gas blanket inert to free radical reactions. The 
monomer may be in gaseous, liquid, or solid form but should be saturated 
with and maintained under the inert atmosphere. Preferred methods are to 
add the monomer as a nitrogen-saturated solid or nitrogen-saturated 
liquid. The most preferred method for this disclosure is to add a 
nitrogen-saturated solution of monomer in the remaining fraction of the 
solvent not added in step (a). 
g) After about 10 minutes, the flask is sealed under nitrogen, and the 
slurry is stirred for 10 more minutes. 
h) The reaction flask is placed in a 30.degree. C. bath and is continuously 
stirred for two days. The rate of stirring depends upon the amount of 
monomer in the mixture and the shape and structure of the reaction vessel. 
The duration of the reaction can be readily varied. The flask contents 
will often thicken slowly but may even solidify into a precipitate-laden, 
viscous slurry. 
i) The reaction is then terminated by addition of 1 weight percent of 
hydroquinone in water or exposure to air. 
j) The reaction mixture is dipped into a volume of water equal to about 10 
times the volume of the reaction and stirred until a uniform reaction 
product is precipitated. If the plant material used in the reaction is a 
mixture of plant compounds, the water used in this precipitation step is 
acidified to pH=2 by addition of HCl. 
k) The solid is recovered by filtration and dried under vacuum at 
30.degree. C. 
Organic liquids are a suitable solvent for the graff copolymerization and 
preferably an organic polar, aprotic solvent, such as a solvent from Table 
1, is used. Mixtures of these solvents in various proportions can also be 
used such as 50/50 (vol/vol) mixtures of DMSO and 1,4-dioxacyclohexane; 
and a 50/50 (vol/vol) mixture of DMSO with water. 
TABLE 1 
______________________________________ 
Liquids Used in Solution Polymerization of Graft 
Copolymers 
Dimethylsulfoxide (DMSO).sup.a 
Dimethylacetamide 
1,4-Dioxacyclohexane 
Dimethyl formamide 
Water 1-Methyl-2-pyrrolidinone 
Pyridine 
______________________________________ 
.sup.a Most frequently used liquids given in bold print. 
TABLE 2 
______________________________________ 
Lignins Grafted with this Chemistry and Salts Used 
A. SALTS 
Form- 
Name ula Name Formula 
______________________________________ 
Calcium Chloride 
CaCl.sub.2 
Sodium Bromide NaBr 
Sodium Chloride 
NaCl Lithium Bromide 
LiBr 
Potassium Chloride 
KCI Calcium Fluoride 
CaF.sub.2 
Magnesium Chloride 
MgCl.sub.2 
Potassium Bromide 
KBr 
Lithium Chloride 
LiCl Magnesium Fluoride 
MgF.sub.2 
Calcium Bromide 
CaBr.sub.2 
Sodium Fluoride 
NaF 
Magnesium Bromide 
MgBr.sub.2 
Potassium Fluoride 
KF 
Lithium Fluoride 
LiF 
B. VASCULAR PLANT, PLANT T, OR MIXTURE 
OF PLANT COMPOUNDS 
Source 
Pine Aspen Yellow Poplar 
Maple 
Oak Bagasse Bamboo Spruce 
Birch Blank Locust 
Walnut Corn 
Beech Cotton Primrose 
Flower ( Primula vulgaris) 
(Gossypium 
hirsutum) 
Plant Part 
Roots Shoots 
Leaves Seeds 
Bark Twigs Wood Wood Pulp 
Wood fiber 
Wood Wood Veneer Xylem 
Filament 
Phloem Cambium Parenchyma Cellenchyma 
Cells Cells 
Selerenchyma 
Cells 
______________________________________ 
Mixtures of Lignin and Cellulose, Hemicellulose, or PlantProduced, 
Inorganic Minerals. 
The choice of vascular plant, plant part, or mixture of plant compounds is 
apparently general. That is, a whole series of vascular plants obtained by 
different techniques have been grafted by this method, as shown by the 
data of Table 2B. 
In general, these vascular plant parts were dried before being used. Some 
materials were extracted with benzene at 78.degree. C. for 48 hours to 
allow separation tests on the reaction products but these extractions are 
extraneous to the synthesis method and product properties. The plant parts 
come in many forms, varying from boards to mixture of the powdered plant 
compounds listed in Table 2B. Note that the materials listed in Table 2B 
cover grasses, softwoods, and hardwoods. Further, all forms and parts of 
the plant can be grafted. 
TABLE 3 
______________________________________ 
Hydroperoxides Useful in Polymerization of 
Graft Copolymers 
hydrogen peroxide 2-hydroperoxy-1,4- 
3,3-dimethyl-1,2-dioxybutane 
dioxacyclohexane 
Anhydrous Solid Peroxides 
sodium peroxyborate 
magnesium peroxyphthalate 
sodium percarbonate 
______________________________________ 
The hydroperoxide addition can be made by adding an aqueous solution of the 
peroxide for safe handling or the peroxide can be added directly. 
Yield is calculated from the formula: 
##EQU1## 
It is preferred that all reagents used be of reagent grade purity but less 
pure materials may be used if they do not contain inhibitors for the 
reaction. Other changes in this procedure, evident to those skilled in 
synthesis or chemical manufacture, can be made. 
The reaction is allowed to proceed for 1 to 200 hours, with 48 hours being 
a typical reaction time. It is common to terminate the copolymerization by 
addition of a free radical scavenger such as hydroquinone. In the 
examples, parts and percentages are by weight and temperatures are in 
centigrade unless otherwise indicated. 
Indulin AT, a commercial lignin product of the Westvaco Corporation was 
used in some syntheses. Yellow poplar lignin from BioRegional Energy 
Associates of Floyd, Va. was used in some of the reactions. Oak and maple 
veneer was supplied by Masco Corp. of Taylor, Mich. The compound 
1-phenylethene, trivial name styrene, and 2-propene nitrile, trivial name 
acrylonitrile, were obtained from the Laboratory and Research Products 
Division of Kodak, Rochester, N.Y. 14650. The compound 
2-methyl-1,3-butadiene [78-79-5], trivial name isoprene, was obtained from 
the Aldrich Chemical Company as product number I-9,551-1. 
The reagent grade solvents, 1,4-dioxacyclohexane and dimethylsulfoxide, are 
from Mallinckrodt Chemical Company and anhydrous calcium chloride is also 
from Mallinckrodt. Other halide salts used in the experiments came from 
Fisher, J.T. Baker, and Merck Companies. The hydroquinone solution was 1 
weight percent hydroquinone in distilled water. 
The present invention will now be further illustrated by certain examples 
and references which are provided for purposes of illustration only and 
are not intended to limit the present invention. 
EXAMPLE 1 
A total of 1.00 g of yellow poplar lignin and 1.30 g of calcium chloride 
were placed in a 125 mL conical flask containing 22.56 g of 
dimethylsulfoxide. This was labeled solution A. 
A total of 6.07 g of 2-propenamide and 0.46 g of 1-phenylethene were placed 
in a 125 mL conical flask containing 22.57 g of dimethylsulfoxide. This 
was labeled solution B. Solution A was stir-bubbled with nitrogen 
(N.sub.2) for about 11 minutes before 0.964 mL of 29.86 percent, aqueous 
hydrogen peroxide was added to the reaction mixture. N.sub.2 was bubbled 
through the reaction mixture (A) and it was stirred for about 5 more 
minutes. Solution A was then added to solution B, which had been stirred 
and bubbled with N.sub.2 for 19 minutes while A was being initiated with 
hydroperoxide. 
After a short period of stirring and bubbling N.sub.2 through the reaction 
mixture, the flask was stoppered and placed in a 30.degree. C. bath for 2 
days. The reaction was not stirred while in the 30.degree. C. bath. The 
reaction was then terminated by adding 7 mL of 1% hydroquinone thereto. 
The reaction mixture was diluted with 100 mL of water and allowed to 
dialyze against pure water for several days. The dilute reaction product 
from the dialysis tube was recovered by freeze drying and found to weight 
5.5 g. The product was labeled 25-128-LSPI. Yield=73.0 weight percent. 
Table 4 gives the results from a series of reactions run to determine if 
1-phenylethylene side chains could be attached to lignin. Example numbers 
of these reactions are shown in parentheses. The synthesis procedure is 
that described in Example 1. The results of Table 4 show that yield falls 
off as the amount of 1-phenylethene in the reaction increases to more than 
50 weight percent of all monomer in the reaction, becoming zero when pure 
1-phenylethene is reacted with lignin. The procedure disclosed in U.S. 
Pat. No. 4,889,902 fails to graft hydrophobic monomers to plant parts. 
Further tests were run to find a new method by which hydrophobic monomers 
could be attached to vascular plants or their parts. Dimethyl acetamide, 
dimethlysulfoxide, 1,4-dioxacyclohexane, tetrahydrofuran, and dimethyl 
formamide were used as solvents during this testing program and sodium 
chloride or calcium chloride was used as a halide salt. These tests showed 
that when the reaction was not stirred, yield was less than the amount of 
lignin originally placed in the reaction. This indicated that the grafting 
reaction and the previous synthesis method had failed. 
Grafting of lignin was achieved by maintaining a shear rate of 150 per 
second in the reaction by stirring the reaction at 4 Hz. The results of 
these stirred reactions are given in Table 5 and show that stirring is 
critical to conducting a synthesis with hydrophobic monomers. The results 
showed that 1-phenylethene reactions must be stirred at 4 Hz, the 
preferred halide salt is calcium chloride, and the preferred solvent is 
dimethylsulfoxide. The reactions of Table 5 were stirred at 4 Hz and 
precipitated in distilled water. The neutral pH of the precipitation media 
may have caused excessive loss of the lignin of sample 30-87-3. 
Examples 9 and 10 of Table 5 show the effect of continuous stirring of the 
reactor with reaction yields of over 94 weight percent from each reaction. 
The data of Tables 4 and 5 thus show that for grafting to occur, a 
reaction mixture containing more than 50 weight percent or 30 mol percent 
nonpolar monomer must be continuously stirred. Specific, quantitative 
stirring rates and the equations by which to calculate them will be 
presented after disclosure of the series of reactions run to determine 
these stirring rates. The reactions were run with different monomers that 
produce plastics. 
Table 6 shows data for a spectrum of reactions run to optimize yield and 
create samples of different molecular weight and composition. All of these 
reactions were stirred at a rate of 4 Hz throughout the synthesis. 
TABLE 4 
______________________________________ 
Grafting Of Yellow Poplar Lignin With 
Monomer Mixtures.* 
Sample (Example) 
Material Added (g) 
Number 1-phenyl- 
2-propen- 
Yield 
25-128- Lignin ethene amide (g) (%) 
______________________________________ 
LSP1 (1) 1.00 0.460 6.077 5.5 73.0 
LSP2 (2) 1.00 0.937 5.757 9.6 125. 
LSP3 (3) 1.00 1.875 5.118 6.6 82.8 
LSP4 (4) 1.00 2.343 4.798 8.0 98.3 
LSP5 (5) 1.00 4.687 3.198 2.3 25.9 
LS (6) 1.00 1.700 0.0 1.1 40.7 
______________________________________ 
*All reactions initiated with calcium chloride and hydrogen peroxide. 
TABLE 5 
______________________________________ 
Use of Different Salts in Grafting Reaction. 
Material Added (g) 
1- 
phenyl 
Sample Salt ethyl- Yield 
Number Used Lignin ene NaCl H.sub.2 O.sub.2 
(g) (%) 
______________________________________ 
30-86-1 
NaCl* 2.00 18.76 2.79 1.9 mL 
7.06 34.0 
(7) 
30-86-2 
NaCl# 2.00 18.76 2.87 1.9 mL 
4.75 22.9 
(8) 
30-87-1 
CaCl.sub.2 * 
2.00 18.77 2.02 1.9 mL 
19.69 
94.8 
(9) 
30-87-2 
CaCl.sub.2 .sup.# 
2.00 18.75 2.07 1.9 mL 
19.93 
96.0 
(10) 
30-87-3 
CaCl.sub.2 
2.00 18.76 2.02 0.0 mL 
1.59 7.7 
(11) 
______________________________________ 
*Low solvent content reaction. 
#High solvent content reaction. 
() = example number. 
TABLE 6 
__________________________________________________________________________ 
Composition and Yield of Copolymer Reaction Mixtures. 
Composition (g) 
Example 1-Phenyl Yield Sample 
Number 
Lignin 
ethene 
CaCl.sub.2 
H.sub.2 O.sub.2 (mL) 
Solvent 
(g)/(wt. %) 
Number 
__________________________________________________________________________ 
12 2.00 
18.76 
2.02 
1.0 20.04 
17.80/85.74 
30-136-1 
13 2.00 
18.76 
2.01 
2.0 20.00 
20.28/97.69 
30-136-2 
14 2.00 
18.76 
2.07 
3.0 19.99 
20.37/98.12 
30-136-3 
15 2.01 
18.77 
2.02 
4.0 20.02 
19.10/91.92 
30-137-1 
16 2.01 
18.78 
2.02 
5.0 20.02 
18.53/89.13 
30-137-2 
17 3.03 
18.78 
2.00 
2.0 20.00 
19.14/87.76 
30-144-3 
18 2.00 
18.76 
1.01 
2.0 20.10 
18.84/90.75 
30-114-2 
19 2.01 
18.79 
1.52 
2.0 20.01 
18.77/90.24 
30-114-3 
20 2.00 
18.79 
2.01 
2.0 20.05 
18.81/90.48 
30-115-1 
21 2.01 
18.76 
2.52 
2.0 20.07 
18.98/91.38 
30-115-2 
22 2.01 
18.76 
2.03 
2.0 20.01 
19.52/93.98 
30-111-1 
23 8.00 
28.15 
8.00 
8.0 40.02 
33.16/91.73 
35-102-1 
24 8.04 
18.76 
8.00 
8.0 40.03 
24.14/90.07 
35-102-2 
25 8.01 
9.39 8.00 
8.0 40.10 
15.45/88.79 
35-102-3 
26 8.00 
9.38 2.08 
8.0 40.08 
14.56/83.77 
35-105-1 
27 8.03 
9.38 4.04 
8.0 40.09 
14.98/86.04 
35-105-2 
28 8.02 
18.76 
6.02 
8.0 40.00 
24.93/93.09 
35-110-3 
29 8.05 
9.34 6.00 
8.0 40.05 
15.53/89.30 
35-120-3 
30 8.02 
18.69 
6.00 
8.0 40.24 
23.25/87.05 
35-120-2 
31 2.01 
18.79 
2.02 
3.0 20.10 
19.47/93.74 
30-100-4 
32 8.02 
18.79 
6.03 
6.0 40.02 
24.83/92.61 
35-113-3 
33 8.01 
28.14 
6.01 
8.0 40.09 
29.32/81.11 
35-130-3 
34 8.01 
9.38 6.28 
8.0 40.00 
15.89/91.37 
35-105-3 
35 8.00 
28.10 
6.00 
8.0 40.14 
33.02/91.47 
35-120-1 
36 4.00 
14.07 
3.00 
4.0 30.18 
17.11/94.69 
35-127-1 
37 2.00 
18.78 
2.04 
3.0 20.06 
19.13/92.06 
30-151-2 
38 8.06 
9.38 6.00 
8.0 40.05 
15.59/89.39 
35-115-3 
__________________________________________________________________________ 
Reaction 36 was run using hardwood lignin recovered by extracting a residue 
of Masonite manufacture with aqueous base. The residue is called clarifier 
sludge. This and related reactions show that these products can be made 
from all of the plants listed under "Source" in Table 2B. These products 
have been shown to be poly(lignin-g(1-phenylethylene)) by solubility 
tests, extraction tests, and Fourier transform infrared spectrophotometric 
analysis. This shows that the reaction being run on lignin is: 
##STR4## 
The results of examples 12 to 17 show that there is an optimum ratio of 
peroxide to chloride to lignin that produces maximum yield and 
1-phenylethene conversion. The highest yield occurs at a peroxide to 
chloride mole ratio of 0.814. At this ratio, quantitative conversion of 
1-phenylethene to polymer occurs. The reaction of each plant part with 
each ethene monomer will have an optimum mole ratio of hydroperoxide to 
halide ion and there will be weight or mole ratios between the plant part 
and hydroperoxide or chloride ion which produce maximum yield. At present, 
these ratios can only be determined experimentally. 
The data from examples 18 to 21 and 26 to 28 show that there is a broad 
range of halide ion concentrations that produce high but not maximum 
yield. Maximum yield of copolymer can be obtained only when a specific 
concentration ratio exists between chloride ion, hydroperoxide, and the 
plant part. Further data, not given here, prove that the weight fraction 
of plant part to monomer can be varied from 0 to 1. The copolymer's plant 
content can thus be varied between 0 and 100 weight percent to give any 
particular plant content desired. Most of the examples of Table 6 were 
terminated by opening the reaction vessel to air. 
Further tests of reactions between lignin and 1-phenylethene showed that 
run-away reactions which result in explosions or loss of anaerobic 
atmosphere occur if the starting materials are not kept at or below 
30.degree. C. as the reaction is started. Temperature control must be 
maintained throughout the grafting process and becomes particularly 
important when dealing with gaseous monomers. Prereacton cooling not only 
promotes high yield, it also increases the safety of the reaction process, 
particularly during reactions with very reactive plant parts. The results 
of reactions with base-extracted, hardwood lignin or kraft pine lignin 
show that this chemistry allows mixtures of all mass ratios or mole ratios 
of lignin to monomer, to be graft copolymerized at high yield. This 
process therefore makes unique materials that can not be obtained by any 
other method of grafting. These reactions also showed that base-extracted, 
hardwood lignin reacted particularly rapidly with 1-phenylethene. The 
kinetics of these reactions depend on both plant part and monomer and can 
not be predicted at the present time. 
Although plants are incredibly complex chemical systems, none of the 
components indigenous to the plant terminate or interfere with this 
grafting process. The incredible uniqueness and novelty of the general 
applicability of this chemistry to the materials of Table 2B can be seen 
by the fact that even small amounts of such common materials as rust will 
completely terminate the reaction and completely inhibit grafting. 
To obtain high purity research samples, some further purification steps are 
used. The original solid precipitated upon terminating the reaction is 
labeled (sample number A) and is extracted with benzene for 48 hours. The 
benzene-soluble material is recovered by evaporating the benzene and the 
material is labeled fraction BenEx. The solid not dissolved in benzene is 
labeled fraction B and is washed with 0.5M sodium hydroxide. This solution 
is filtered and the filtrate is dialyzed against water for 3 to 5 days 
using dialysis tubing. The solid, filtered from the base, is dried and 
labeled fraction C. The diluted solution is then dried or freeze dried to 
recover product fraction D. This process converts the original sample, 
(sample numberA), to four different fractions: (sample numberBenEx), 
(sample numberB), (sample numberC), and (sample numberD). 
None of these fractions are pure, but they each contain different fractions 
of a macromolecular, surface active agent which occupies interfaces 
between a woody phase and a plastic phase, couples vascular plant parts to 
a plastic phase, degrades under fungal attack, forms insulating, cellular 
solids useful as packaging for hot items, forms structured, heterogeneous 
solids with an internal structure which forms automatically upon cooling, 
and can release fragments of the original molecule over time as fungi 
compost the grafted plant part and release repeat unit fragments into the 
environment. Fraction BenEx, the benzene-soluble part of the product, 
contains poly(1-phenylethylene) homopolymer and the graff copolymer that 
has long 1-phenylethylene chains on it. Product C contains graff copolymer 
with medium-sized 1-phenylethylene chains on it. Product D is any 
unreacted lignin and graff copolymer with tiny 1-phenylethylene chains on 
it. These fractions and kraft pine lignin were tested for chemical 
composition by Fourier transform infrared spectroscopy with chemical 
identification being obtained from the lignin absorbence peak at 14.66 
micrometers wavelength and the poly(1-phenylethylene) absorbence peak at 
14.29 micrometers. The infrared spectroscopy results show that the two 
components of the reaction product, lignin and 1-phenylethylene, are 
distributed throughout the product's fractions and must be chemically 
bound. These results farther prove that both plant part and sidechain are 
distributed throughout the fractionated product and, thus, that the plant 
part put into the reaction has been quantitatively grafted. 
Further tests were run on previously synthesized samples of 
poly(lignin-g-(1-phenylethylene)) to observe and display its thermoplastic 
properties. A sample of the graft copolymer was placed between two teflon 
sheets and the assemblage placed on top of a hot plate and weighed down 
with a second hot plate. The lower hot plate was already heated to 167 
+/-2.degree. C. and the upper hot plate was already heated to 164 
+/-2.degree. C. The copolymer samples were kept between the hot plates for 
40 to 60 seconds and then the assemblage was allowed to cool. Compressive 
force was 1 to 1.5 metric tons. Upon opening the enveloping teflon plates, 
a hard, brittle sheet was found to have been compression cast from the 
powdered copolymer. The sheets were clear to opaque, brown plastics with a 
thickness of approximately 0.5 to 1 mm. The physical properties of the 
sheet and its color varied according to which copolymer had been chosen 
for compression casting. All were dark brown and were a darker brown than 
the powder taken to cast the sheet. The copolymers cast were checked for 
color and brittleness. The results of the tests are summarized in Table 7. 
The pure lignin sample was the material used as a reagent in a number of 
the grafting reactions previously described. Poly(1-phenylethylene) was a 
commercial product supplied by the manufacturer and used as a comparison 
material. Examination of the films by eye and twisting the films to break 
them were used to rank the materials for tint and stiffness. The results 
clearly show that the graft copolymer is a more ductile and thermoplastic 
material that will flow at higher temperature and be ductile under common 
application conditions for a plastic at 25.degree. C. and 1 atmosphere 
pressure. Because lignin has a glass transition temperature above 
150.degree. C., it is a 
TABLE 7 
______________________________________ 
Experiments in Forming Plastic Films From Copolymer. 
Brittleness 
And 
Sample Lignin (Wt. %) Yield Darkness 
(Example) 
in Reaction 
in Original 
(Weight of Plastic 
Number Mixture Product %) Films 
______________________________________ 
1-134-4 100. 100. -- Maximum 
35-105-3A(34) 
46.0 50.41 91.37 Great but 
Decreasing 
35-110-3A(28) 
30.0 32.17 93.09 Large but 
Decreasing 
35-130-3A(33) 
22.1 27.32 81.11 Medium 
but 
Decreasing 
35-111-1A(22) 
9.68 10.30 93.98 Lower and 
Decreasing 
Poly(1-phenyl 
0.0 0.0 -- Least 
ethylene) 
______________________________________ 
brittle, inflexible material while the grafted plant products can be bent 
and are ductile plastics. Glass transition temperature is a characteristic 
temperature point in amorphous polymers at which molecular segments 
containing 50 or more backbone atoms begin to move. It is defined in 
Chapter VI, pages 209+, of the Polymer Handbook, Third Edition, J. 
Brandrup, E. H. Immergut, Eds., Wiley-lnterscience, (1989). 
The data of Table 7 clearly demonstrate that the reaction products of 
lignin and 1-phenylethene are thermoplastics. Having established that the 
copolymers are plastics, data from a series of other thermoplastics will 
be presented to show the breadth and generality of the new method of 
synthesis and show the broad spectrum of new compositions of matter that 
can be made. After examples of these new compositions of matter are given, 
the unique and novel properties of these materials; surface activity, 
capacity to populate interlaces, activity as a coupling agent, 
degradability, use as an insulating foam, self forming composites and use 
as a slow release agent; will be described and data on these properties 
will be given. 
In the following examples, the compound 2-propene nitrile, trivial name 
acrylonitdle, was used in the reactions. 
##STR5## 
A series of copolymers were made by the procedures of examples 1 to 5 and 
are listed in Table 8. These data again show that increasing the amount of 
plastic-producing monomer, 2-propene nitrile, in the unstirred reaction 
mixture sharply reduces the yield of the reaction, leading to failure of 
the unstirred reaction. Further study showed that yield could be made 
quantitative by using the stirred reaction procedure of Table 5, example 9 
for reactions with only 2-propene nitrile as monomer. A series of 
copolymers made by the mixed reaction procedure of example 9 are listed in 
Table 9. These data clearly show that the synthesis procedure with 
continuous mixing produces a grafted product with a plastic sidechain and 
efficient polymerization. Rate of stirring for 2-propene nitrile reactions 
is 0.4 Hz. 
TABLE 8 
______________________________________ 
Reactions to Form Graft Copolymer.* 
Reagents 
Kraft (g) 2- Yield 
Sample Pine 2-Propene- 
Propen- 
in Weight 
Number Lignin nitrite amide Grams Percent 
______________________________________ 
19-145-9(39) 
0.50 0.35 4.17 4.82 96.4 
19-146-8(40) 
0.50 0.78 3.74 4.91 97.8 
19-147-7(41) 
0.50 1.19 3.33 3.50 69.7 
19-150-8(42) 
0.50 0.79 3.75 3.28 65.1 
______________________________________ 
*The sidechain of these molecules is itself a random copolymer. 
TABLE 9 
______________________________________ 
Composition and Yield of Copolymer Reaction Mixtures. 
Composition (g) 
2- Yield 
Sample Propene H.sub.2 O.sub.2 
Sol- (g)/ 
Number Lignin Nitrile CaCl.sub.2 
(mL) vent (wt. %) 
______________________________________ 
26-74-2(43) 
4.10 9.35 3.05 4.0 20.04 
13.86/ 
103.0 
26-74-3(44) 
3.95 6.08 3.07 4.0 20.07 
9.83/98.0 
26-74-4(45) 
4.05 3.13 3.02 4.0 20.57 
6.34/ 
88.30 
26-74-5(46) 
4.02 6.15 3.05 4.0 25.02 
10.14/ 
99.71 
26-74-6(47) 
4.00 6.16 2.51 5.0 20.01 
9.29/ 
94.29 
______________________________________ 
In the following examples, the monomer used was 2-methyl-1,3-butadiene 
78-79-5]. Two samples of this product are synthesized with the 
compositions of Table 8 and the continuous agitation procedure of Table 5, 
example 9. The stirring rate was 1.33 Hz. These products were both plastic 
and elastomeric, possessing the property of low modulus, capacity to 
recover shape, and ability to increase elastic modulus with increase in 
distention of the solid. Results of these synthesis were listed as Table 
10. 
##STR6## 
In another set of examples, the monomers used were 2-propene nitrile 
[107-13-1] and 1-phenylethene [100-42-5]. A number of these copolymers 
have been made. The formula for the sidechain is the random copolymer 
illustrated by the structure of equation 3, where the ratio of m to n is 
0.425 to 0.534. These materials were designed to have an m to n ratio 
spread about a value of 
##STR7## 
0.44. This ratio allowed the graff copolymer to miscibly dissolve in PHBV 
(poly(3-hydroxybutrate-r-3-hydroxyvalerate)) since it produced the same 
solubility parameter in the sidechain as in PHBV. Solubility parameter is 
calculated from a substance's heat of vaporization to a gas at zero 
pressure, E, and its molar volume, V=the amount of space taken up by one 
mole of the material. Solubility parameter is the square root of heat of 
vaporization divided by molar volume, S=(E/V).sup.0.5. 
TABLE 10 
______________________________________ 
Composition and Yield of Copolymer Reaction Mixtures. 
Composition (g) 
Sample 2- 
(Ex- methyl- Reaction 
ample) 1,3-Buta- H.sub.2 O.sub.2 
Sol- Yield 
Number Lignin diene CaCl.sub.2 
(mL) vent (g)/(wt. %) 
______________________________________ 
26-71-2 
4.11 9.32 3.02 4.0 20.29 
4.21/31.3 
(48) 
26-71-3 
4.01 3.14 3.05 4.0 20.32 
4.39/61.4 
(49) 
______________________________________ 
A summary of a series of syntheses which formed these 2-propene nitrile and 
1-phenylethene copolymers is given in Table 11. These reactions were 
stirred at a rate of approximately 3.29 Hz. The exact rate can be 
calculated from the dipole moment of the monomers in the reaction and 
their respective mole fractions. The dipole moment of the mixture, 
.mu..sub.mix, is given by 
##EQU2## 
where, for n monomers in the reaction mixture, .mu..sub.i is the dipole 
moment of monomer "i" and X.sub.i is the mole fraction of monomer "i". The 
mole fraction of any monomer is the number of moles of that monomer in the 
reaction divided by total number of moles of monomer in the reaction. The 
reaction being run here is the random copolymerization illustrated by the 
formula: 
##STR8## 
TABLE 11 
__________________________________________________________________________ 
Lignin-Co-(1-P.Ethylene+2-Propene Nitrile) Samples. 
Reaction Contents 
Sample 
Lignin 
1-Phenyl 
2-Propene- 
DMSO 
CaCl.sub.2 
H.sub.2 O.sub.2 
Yield 
Number 
(g) ethene (g) 
nitrile (g) 
(g) (g) (ml) 
(wt. %) 
__________________________________________________________________________ 
44-15-1(50) 
4.15 
4.71 5.62 22.03 
3.00 
4.00 
92.5 
44-15-2(51) 
4.02 
4.80 5.58 23.28 
3.09 
4.00 
81.4 
44-15-3(52) 
4.13 
4.89 5.38 22.13 
3.04 
4.00 
95.6 
44-15-4(53) 
4.16 
5.00 5.32 22.54 
3.05 
4.00 
79.4 
44-15-5(54) 
3.97 
5.22 5.30 20.06 
3.22 
4.00 
78.8 
44-15-6(55) 
3.94 
5.30 5.19 20.13 
3.15 
4,00 
82.3 
44-15-7(56) 
4.03 
5.42 5.45 23.97 
3.51 
4.00 
84.6 
__________________________________________________________________________ 
Note that these examples clearly show that many different copolymers with 
random order of different repeat units in the sidechain can be made by the 
procedures illustrated here. 
In another set of examples, the monomer used was 
4-methyl-2-oxy-3-oxopent-4-ene, [80-62-6]. The structure of the compound 
is: 
##STR9## 
The structure of the product is: 
##STR10## 
Different bonds through the 4-methyl-2-oxy-3-oxopent-4-ene monomer unit 
are possible. The results of a number of these reactions are given in 
Table 12. These data clearly show that numerous, different graff 
copolymers can be made by conducting this reaction with lignin and 
monomers that react by free radical polymerization. 
TABLE 12 
______________________________________ 
Poly(Lignin-G-(1-(2-Oxy-1-OxoPropyl)ethylene)) 
Formed Under Various Reaction Compositions 
30% 
SAMPLE LIGNIN A* CaCL.sub.2 
H.sub.2 O.sub.2 
DMSO YIELD 
No. (g) (g) (g) (mL) (mL) (%) 
______________________________________ 
1-4(57) 0.50 3.41 0.75 1.00 5.33 99.09 
2-1(58) 1.50 10.20 0.60 0.50 16.02 93.50 
2-5(59) 1.50 10.20 0.60 5.00 16.02 96.27 
3-1(60) 1.50 3.59 0.60 1.50 16.02 94.70 
3-2(61) 1.50 5.26 0.60 1.50 16.02 96.30 
3-3(62) 1.50 9.20 0.60 1.50 16.02 94.67 
3-4(63) 1.50 12.38 0.60 1.50 16.02 94.16 
3-5(64) 1.50 14.30 0.60 1.50 16.02 97.15 
3-6(65) 1.50 17.48 0.60 1.50 16.02 96.68 
4-1(66) 1.00 9.20 0.40 1.00 10.68 94.51 
4-2(67) 2.00 9.20 0.80 2.00 21.36 98.67 
4-3(68) 3.00 9.20 1.20 3.00 26.70 95.41 
4-4(69) 4.00 9.20 1.60 4.00 42.72 97.20 
4-5(70) 5.00 9.20 2.00 5.00 53.40 94.72 
4-6(71) 6.00 9.20 2.40 6.00 64.08 98.36 
______________________________________ 
*4-methyl-2-oxy-3-oxopent-4-ene. 
EXAMPLE 72 
A grafted product may be made from a plant part from virtually any plant 
and I-chloroethene. The structure of I-chloroethene is: 
##STR11## 
The monomer or a mixture of this monomer and any other ethene monomer 
mentioned herein can be polymerized with any plant part in any one of a 
series of solvents by dispersing the plant part and any of a series of 
metal halide salts, with calcium chloride the preferred salt, in the 
solvent. Typical solvents are listed in Table 1 and typical salts are 
listed in Table 2A. Other solvents and salts can be used. The 
polymerization is initiated by adding a hydroperoxide to the reaction 
mixture. The monomer, I-chloroethene, is added to the reaction mixture 
either as a cooled liquid or as an ambient temperature gas and the 
reaction is allowed to proceed for between 1 and 96 hours, 48 hours 
preferred, with stirring at a rate of 0.93 Hz. The gaseous monomer may be 
added by bubbling. The polymer is recovered by precipitation in 
non-solvents or evaporation of solvent. The structure of the product is: 
##STR12## 
Syndiotactic, isotactic, or atactic bonds through the I-chloroethene 
monomer unit are possible. 
Polymerizations of 1-chloroethene were run in a 1 m long, heavy walled, 
glass tube. The mixed lignin, calcium chloride, and dimethylsulfoxide was 
placed in the tube and saturated with nitrogen. It was frozen in dry ice. 
The 1-chloroethene was condensed in a 10 cm side arm using liquid nitrogen 
as coolant before a 30 volume percent solution of hydrogen peroxide in a 
glass vial was placed on the frozen dimethylsulfoxide solution. The glass 
tube reactor was evacuated, sealed, and rotated once the dimethylsulfoxide 
solution had thawed. The amount of lignin added to the reaction was 2.0g 
and the amount of 1-chloroethene was approximately 4.5g (measured by 
volume, not by weight). Over 48 hours, the reaction mixture thickened and 
a gelatinous solid formed in the tube. The solid recovered from the tube 
did not dissolve in 2M aqueous base, a common and powerful solvent for 
lignin. Since thermoplastic lignin with a poly(1-chloroethylene) sidechain 
would not be soluble in any aqueous solution, this was strong proof of 
graff copolymerization of this gaseous monomer. 
EXAMPLE 73 
The method of Example 72 is used except that the compound is made from a 
plant part from any vascular plant and ethene. The structure of ethene is: 
EQU CH.sub.2 .dbd.CH.sub.2 
The rate of stirring is 1.38 Hz. The structure of the product is: 
EQU Plant Part-(--CH.sub.2).sub.n -- 
EXAMPLE 74 
The method of Example 72 is used except that the compound is made from a 
plant part from any vascular plant and perfluoroethene. The structure of 
perfluoroethene is: 
EQU CF.sub.2 .dbd.CF.sub.2 
The rate of stirring of the reaction is 1.4 Hz. The structure of the 
product is: 
EQU Plant Part-(--CF.sub.2).sub.n -- 
EXAMPLE 75 
The method of Example 71 is used except that the compound is made from a 
plant part from any vascular plant and 2-chloro-1,3-butadiene. The 
structure of 2-chloro-1,3-butadiene is: 
##STR13## 
The compound produced by this reaction will be poly(plant 
part-g-(2-chlorobut-1,4-diyl-2-ene) or any of the structural enantomers of 
the free-radical polymerization of 2-chloro-1,3-butadiene). One structure 
of the product is, 
##STR14## 
but 1,2; 3,4; or other polymerization patterns make different structures 
in the product. Different bonds through the 2-chloro-1,3-butadiene repeat 
unit are possible such as 1,2-ylene bonding. 
EXAMPLE 76 
The method of Example 71 is used except that the compound is made from a 
plant part from any vascular plant and dichloroethene. The structure of 
dichloroethene is: 
EQU CH.sub.2 .dbd.CCl.sub.2 or CHCl.dbd.CHCl 
The stirring rate of the reaction is 0.8 to 1.4 Hz with the rate increasing 
as the mole fraction of trans-1,2-dichloroethene increases from 0 to 1. 
The structure of the product is: 
EQU Plant Part-(--CH.sub.2 --CCl.sub.2).sub.n -- or 
EQU Plant Part-(--CClH--CClH).sub.n 
Syndiotactic, isotactic, head-to-tail, or other bonds through the 
dichloroethene repeat unit are possible. 
EXAMPLE 77 
The method of Example 72 is used except that the compound is made from a 
plant part from any vascular plant and I-propene. The structure of 
I-propene is: 
EQU CH.sub.2 .dbd.CH--CH.sub.3 
The stirring rate of the reaction is 1.25 Hz. The structure of the product 
is: 
##STR15## 
Syndiotactic, isotactic, and atactic bonds through the I-propene repeat 
unit are possible. 
EXAMPLE 78 
The method of Example 71 is used except that the compound is made from a 
plant part from any vascular plant and 2-oxy-3-oxopent-4-ene. The 
structure of 2-oxy-3-oxopent-4-ene is: 
##STR16## 
The structure of the product is: 
##STR17## 
Head to tail, syndiotactic, or other bonds through the 
2-oxy-3-oxopent-4-ene repeat unit are possible. 
EXAMPLE 79 
The method of Example 71 is used except that the compound is made from a 
plant part from any vascular plant and 2-oxo-3-oxypent-4-ene. The 
structure of 2-oxo-3-oxypent-4-ene is: 
##STR18## 
The structure of the product is: 
##STR19## 
Syndiotactic, isotactic, or head-to-tail bonds through the 
2-oxo-3-oxypent-4-ene repeat unit are possible. 
EXAMPLE 80 
The method of Example 71 is used except that the compound is made from a 
plant part from any vascular plant and 2-methyl-2-propenoic acid. The 
structure of 2-methyl-2-propenoic acid is: 
##STR20## 
The structure of the product is: 
##STR21## 
Syndiotactic, isotactic, or head-to-tail bonds through the 
2-methyl-2-propenoic acid repeat unit are possible. 
In the next example, the monomer is 2N-methyl-2-imino-3-oxopent-4-ene, 
##STR22## 
EXAMPLE 81 
A total of 0.50 g of lignin and 0.63 g of calcium chloride were placed in a 
125 mL conical flask containing 11.28 g of dimethylsulfoxide and were 
dissolved. The mixture was stir-bubbled with nitrogen (N.sub.2) for about 
2 minutes before 0.482 mL of hydrogen peroxide were added to the reaction 
mixture. N.sub.2 was bubbled through the reaction mixture for about 2 more 
minutes, the system was stirred for about 3 minutes, and 4.52 g of 
2N-methyl-2-imino-3-oxopent-4-ene (I) was added. After about 4 minutes of 
stirring and bubbling N.sub.2 through the reaction mixture, the flask was 
stoppered. It was then placed in a 28.degree. C. bath for 2 days. The 
reaction was then terminated by adding 0.5 mL of 1% hydroquinone and 100 
mL of water thereto. The solution remained single phase during this 
dilution and smelled sweet. The dilute solution was placed in a dialysis 
tubing and dialyzed against water for 3 days. The dilute reaction product 
in the dialysis tube was centrifuged at 5000 rpm for 40 minutes in a 
Sorvall centrifuge using a GSA head. The solids in the supernate were 
recovered by freeze drying and found to weigh 1.92 g. The product was 
labeled 26-16-1. Yield =38.24 weight percent. 
The previous examples and discussion have shown that reactions conducted 
with hydrophobic monomers will not produce grafting unless the reaction is 
continuously stirred. Further, the rate of stirring depends on the monomer 
being reacted with the plant material. The rate of stirring which produces 
grafting and allows high yield of graft copolymer must be determined from 
the monomer's dipole moment and its solubility in water. The symbol for 
dipole moment is N- and the property is expressed in units of debye, 
abbreviated as a "D". The dipole moment of a molecule is the distance in 
centimeters between separated accumulations of positive and negative 
charge times the magnitude of one of the accumulations of charge, 
expressed in electrostatic units. These charge separations are structural 
features of a molecule caused by its atomic structure and are therefore 
characteristic of the molecule. 
The dipole moments and solubility limits of a group common monomers are 
given in Table 13. Those monomers that have a solubility in water at 
30.degree. C. of more than 200 g of monomer per 100 g of water and a 
dipole moment of more than 1.2, need not be stirred to produce graft 
copolymer. Those monomers that have a solubility of less than 5 g of 
monomer per 100 g of water at 30.degree. C. and a dipole moment of less 
than 1.8, must be stirred to produce graft copolymer from the grafting 
reaction. The rate of stirring is determined by the dipole moment of the 
monomer. The value of the dipole moment, .mu., of the monomer is expressed 
in debye units, D, where 1 D=3.33564.times.10.sup.-30 coulomb-meter. Note 
that there is no contradiction between the solubility-dipole moment limits 
just propounded. The monomer which must simultaneously have a solubility 
in water at 30.degree. C. of more that 200 g of monomer per 100g of water 
and a dipole moment of more than 1.2, before it need not be stirred in a 
grafting reaction. Monomers that Simultaneously have a solubility of less 
than 5 g of monomer per 100 g of water at 30 .degree. C. and a dipole 
moment of less than 1.8, must be stirred to produce graft copolymer from 
the grafting reaction. 
If the absolute value of the stirring rate of the solution in Hz is labeled 
.vertline.x.vertline. and related to the dipole moment of the monomer, a 
quadratic equation is produced that acts as a guide for the design of a 
reaction. The equation relating absolute value of stirring rate to dipole 
moment is a.vertline.x.vertline..sup.2 +b.vertline.x.vertline.+c=.mu., 
where a=0.0024719 D/Hz.sup.2, b=-0.3516 D/Hz, and c=1.381 D. Stirring rate 
is actually controlling "tip speed" of the stirring bar. "Tip speed" is 
the velocity of the ends of the stir bar or paddle in the reaction tank. 
This "tip speed" is a critical variable in mixing. Shear rate is 
approximately 12 times stirring rate in Hz. Shear stress is equal to 
viscosity times shear rate and shear stress is the fundamental value 
controlling the mechanochemistry of phase stability and mixing in the 
reaction. The reaction mixture should have a shear rate perpendicular to 
the direction of stirred flow of between 0.01 per second and 6,000 per 
second. High shear rates in the reaction should be avoided because they 
will cause the formed polymer to mechanically degrade. 
TABLE 13 
______________________________________ 
Dipole Moments and Solubility Limits of Some Common 
Monomers. 
Solubility Limit 
Monomer Dipole.sup.# 
in 100 g of Water 
Name Moment at 30.degree. C. 
______________________________________ 
1-Bromoethene 1.28 insoluble 
1-Chloroethene 1.44 0.86 
1-Fluoroethene 1.427 insoluble 
1,3-Butadiene 0.0 insoluble 
2-Propenamide 1.38* 215.5 
2-Methylprop-2-enoic Acid 
1.65 miscible 
3-Oxy-2-oxopent-4-ene 
1.70 2.33 
Cyclopentene 0.93 insoluble 
Pentyne 0.86 insoluble 
2-Methyl-1,3-butadiene 
0.15 insoluble 
1,3-Pentadiene 0.68 insoluble 
4-Methyl-2-oxy-3-oxopent-4-ene 
1.60 less than 2.0 g 
1-Phenylethene 0.37 insoluble 
______________________________________ 
.sup.# Data from "Tables of Experimental Dipole Moments, Aubrey Lester 
McClellan, W.H. Freeman and Company, San Francisco, (1963) 
*Dipole moment calculated from an AM1 quantum mechanical calculation on 
the planar 2propenamide molecule. 
Before proceeding to examples of structured plant parts that are grafted, 
it is important to document the novel and unexpected properties of the 
products just made. These materials have been shown to be thermoplastic, 
but they also occupy interfaces between wood and plastic; couple wood and 
plastic phases; spontaneously form internally structured solids; increase 
binding strength between wood and plastic phases; form insulating, 
hydrophobic foams; form a product in which both components, backbone and 
sidechain, degrade under fungal attack; and during this degradation, 
release fragments from either backbone or sidechain into the environment 
to produce a time-dependent concentration of that degradation product. 
The grafted products have the amazing property of being surface active 
materials. This was shown by the capacity of these molecules to form 
emulsions between incompatible fluid phases and to bond and coat wood 
surfaces. The lignin grafted with 1-phenylethene formed microemulsions 
between benzene and aqueous base. This middle phase was declared a 
microemulsion because it remained stable over a period of weeks after the 
copolymer and two fluid phases were shaken together. The microemulsion was 
made from 60 mL of 0.5M aqueous sodium hydroxide mixed with a 3.75 weight 
percent solution of copolymer in 20 mL of benzene. The samples were 
prepared in a graduated cylinder, capped with a rubber stopper, shaken and 
allowed to stand for 6 months while the phase volumes were measured. The 
copolymers used were Examples 14, 23, 24, and 25. The copolymer from 
example 14 formed the largest microemulsion between the two fluids by 
converting 37 volume percent of the fluid to a middle phase. The other 
copolymers formed progressively smaller volumes of middle phase. Pure 
lignin, poly(1-phenylethylene), and mixtures of the two separate chemicals 
did not form microemulsions. The capacity of the grafted products to form 
microemulsions can be estimated from the weight percent of plant product 
and sidechain in the reaction product and the solubility parameters of 1. 
the two graft product parts and 2. the two fluids being mixed. A broad 
spectrum of fluids can be formed into microemulsions using different 
sidechains in the grafted product. 
These products also occupy surfaces on wood and act to alter the wetting 
properties of the plant material. Contact angle measurements were used in 
testing how well the graft copolymer acts as a wetting agent for wood. The 
products made by grafting plant parts are such wetting agents and we 
tested them by measuring how much the materials changed the contact angle 
of water on birch wood (Betula albo-sinensis septentrionalis). The dynamic 
contact angle measurement was based on the Wilhelmy plate technique. The 
contact angle of birch is 50.8.degree., that of lignin is 87.degree., and 
that of pure poly(1-phenylethene) is 105.degree.. The treated birch 
samples were prepared by spreading a 5 or 10 weight percent solution of 
graft copolymer in dimethyl formamide on the wood surface with a glass rod 
and drying the coated wood. 
The grafted plant parts and lignin gave smooth, adherent surface coatings 
on the wood. Plastics and plastic-plant part mixtures did not give 
adherent coatings. Birch surfaces treated with plastic or plastic-plant 
part mixtures develop solid flakes on the surface which fall off with time 
or any physical contact. Further, the adherent, grafted coatings change 
the wetting behavior of the wood. Sample 35-110-3A, the product of example 
28, changed the contact angle of water on birch from 50.8.degree., water 
wet, to 110.degree. for product 3A, 99.1 .degree. for fraction 3B, and 
119.5.degree. for fraction 3BenEx. The fractions and the means of 
obtaining them are defined in a previous discussion of characterization. 
Sample 35-120-1, the product of example 35, changed contact angle from 
50.8.degree. to 107.8.degree. for product 1 A, 99.1 .degree. for 1 B, and 
114.degree. for fraction 1BenEx. Note that the capacity to change wood 
wetting behavior varied with the fraction applied to the surface. 
Generally, the fraction extracted from the reaction product and recovered 
from the extraction solvent (BenEx) changes the contact angle most with 
lesser change produced by the original reaction product(A) and the 
extraction residue(B). These data show the application rules for this new 
technology of surface alteration by novel, grafted plant parts. Those 
product fractions with the longest sidechains alter contact angle most 
while products with smaller sidechains alter contact angle to a lesser 
degree. These same treatments and tests have been performed with wood and 
plant parts grafted with 2-propene nitride, 2-propene 
nitrile/1-phenylethene randomly repeating units, or 
2-oxy-3-oxo-4-methylpent-4-ene. 
These data show that the new products of lignin and plant parts are surface 
active, preferentially orienting the lignin or plant portion of the 
product towards wood while the plastic sidechain is oriented outward to 
create a new surface with different wetting properties. Thus, these 
copolymers are surface-active, coupling agents which can bind wood to 
hydrophobic phases such as plastic. This coupling process works best when 
the wetting agent has been synthesized so that the sidechain attached to 
the lignin during the preparation of the macromolecular, surface active 
agent is chemically identical to the plastic hydrophobic phase that is to 
be bound or connected to the wood. Thus, to bind poly(1-phenylethylene) 
[Trivial name=polystyrene] to wood, coat the wood with 
poly(lignin-g-(1-phenylethylene)) and to bind poly(1-cyanoethylene) 
[Trivial name=polyacrylonitrile or orlon] to wood, coat the wood with 
poly(lignin-g-(1-cyanoethylene)). It is also possible to bind the coated 
wood to any plastic phase that will form a polymer alloy with the 
sidechain of the copolymer. Polymers that are preferred blending or 
binding phases for use in this disclosure can be identified by 
thermodynamic data or experiment. The most convenient datum for 
identifying a polymer to bind to the coated wood is solubility parameter. 
Generally, these polymers are those with a solubility parameter that is 
within five, and preferably within two, units of the solubility parameter 
of the sidechain attached to the plant part. 
The wood is best coated by melted or dissolved copolymer. The binding of 
plastic to coated wood is best done with rolling operations such as 
calendering or coating; stretching operations such as film casting or film 
blowing; or cyclic processes such as injection molding or thermoforming. 
Since the coated product contains wood, a structured phase, care must be 
taken in all operations to avoid breaking or crushing the wood. It is 
preferred to heat the polymer to or above its glass transition temperature 
during the binding process. 
The coupling of wood by a grafted plant part to a plastic, that has the 
same or similar composition as the sidechain on the plant part, increases 
the binding strength of the plastic to the wood. This was proven by 
performing lap shear tensile strength tests on birch strips onto which 
were injection molded blocks of plastic. The samples with a grafted 
product coating with the same repeat units in the sidechain as in the 
plastic gave 20 to 50 percent higher tensile strength. The coupling 
experiments were performed as follows. Birch Depressors, a medical product 
of 1.75 mm thickness from Solon Manufacturing Company, Solon, Maine 04979 
were cut into suitable sizes to match an injection mold. Kraft pine lignin 
was reacted into a graff copolymer as previously described. The 
homopoly(1-phenylethylene) used in coupling tests is a recovered fraction 
of the reaction product of mechanical pulp and 1-phenylethene. Copolymer 
was prepared as a 10 weight percent solution in dimethylformamide. Coat 
the wood surface with the sample solutions and dry the coated wood slabs 
in a hood at room temperature for 24 hours. Store the dried wood slabs in 
a desiccator at room temperature and 50+5 percent relative humidity. The 
plastic phase was Amoco RIPO, a commercially available 
poly(1-phenylethylene) from Amoco Chemical Company, Naperville, Ill. 
60566. Injection molding was done on a Milberry, Model 50 Mini-Jector. 
Experimental conditions were: Cylinder temperature, 550.degree. F.; Nozzle 
temperature, 340.degree.-350.degree. F.; Pressure, 500 psi; Pressure 
holding time, 12 seconds; and Chilling time, 1-2 minute. 
Adhesion area was be measured for a representative group of molded 
specimens. It averaged 0.4740+0.0006 square inches. Lap shear strength of 
the pieces of wood with plastic injection molded to them was tested on a 
Instron, Model 4200, Universal testing instrument. Experimental conditions 
were: room temperature, 23.degree. C.; room relative humidity: 50 percent; 
Crosshead speed, 2.54 mm/min.; with the sample in hand-fastened grips and 
an aluminum specimen holder. The lap shear strengths of the wood-plastic 
samples are summarized in Table 14. As these data clearly show, it is 
critical for the grafted, two component composition to be between the 
plant and plastic phases. The grafted constituent allows the plastic to 
wet the wood and it can only perform this function if it covers 10 percent 
or more of the surface area of the plant phase. The grafted plant or its 
constituent can be placed on the surface of the plant phase by dry or 
solvent coating, sputtering, melting, or blending operations. 
TABLE 14 
______________________________________ 
Summarized Adhesion Strength Results. 
Coating Material Adhesion Strength (PSI)* 
______________________________________ 
30-151-2A (10.45% lignin) 
351.3 .+-. 31.8 (3) 
30-151-2B (See Ex. 37) 
335.6 .+-. 70.8 (3) 
30-151-2 Ben.Ex 308.4 .+-. 6.4 (3) 
10% Lig. + 90% PS 320.4 .+-. 36.4 (5) 
35-120-1A (24.23% lignin) 
335.6 .+-. 11.8 (3) 
35-120-1B (See Ex. 35) 
330.5 .+-. 42.7 (2) 
35-120-1 Ben.Ex. 303.7 .+-. 31.0 (3) 
24% Lig. + 76% PS 294.0 .+-. 26.9 (4) 
35-110-3A (32.17% lignin) 
280.0 .+-. 44.1 (3) 
35-110-3B (See Ex. 28) 
277.2 .+-. 26.8 (3) 
35-110-3 Ben.Ex. 387.3 .+-. 30.1 (3) 
32% Lig. + 68% PS 282.7 .+-. 38.5 (5) 
35-115-3A (51.70% lignin) 
411.7 .+-. 8.7 (3) 
35-115-3B (See Ex. 38) 
395.0 .+-. 47.7 (3) 
35-115-3 Ben.Ex. 392.7 .+-. 10.2 (3) 
50% Lig. + 50% PS 267.3 .+-. 13.2 (5) 
Poly(1-phenylethene) (PS) 
296.0 .+-. 30.0 (5) 
10% Lig. + 90% PS 320.4 .+-. 36.4 (5) 
24% Lig. + 76% PS 294.0 .+-. 26.9 (4) 
32% Lig. + 68% PS 282.7 .+-. 38.5 (5) 
50% Lig. + 50% PS 267.3 .+-. 13.2 (5) 
Lignin 308.0 .+-. 23.8 (5) 
Blank (treated with DMF) 
293.3 .+-. 17.5 (2) 
Blank (treated with nothing) 
264.8 .+-. 24.0 (4) 
______________________________________ 
*To convert psi to KPa, multiply by 6.8966. Thus, 351.3 psi = 6.8966 
KPa/psi .times. 351.3 psi = 2423 KPa. Number of repetitions of the tensil 
strength test is in parentheses. 
In almost all cases, coating the wood with any of the three fractions of 
the graft copolymer of lignin and poly(1-phenylethene) (Product A, Product 
B, and Product Ben. Ex.) provides stronger adhesion between wood and 
commercial poly(1-phenylethene) than coating the wood with mechanical 
mixtures, pure poly(1-phenylethene), pure lignin, or nothing (blank). As 
the fraction of wood in the 2 phase solid increases, the tensile strength 
of the wood-plastic solid increases toward 175 MPa and the compressive 
strength changes toward 43 MPa. These values are, respectively, the 
tensile strength and compressive strength of wood. The compressive 
strength of the 2 phase solid will be between 5 and 150 megapascals. 
These grafted materials have unique, unexpected properties not seen in 
plastics, the starting reagents, or mixtures of unreacted plant parts and 
plastics. When heated above their glass transition temperature, the 
temperature at which an amorphous solid becomes ductile, and allowed to 
cool, these grafted products spontaneously form solids with a distinct, 
microscopic structure. The formation of stable microdomains within these 
solids is not the bulk phase separation which would occur in a mixture of 
plant part and plastic. Such a mixture would form large domains of the 
components of the mixture and these "clumps" made up of either phase would 
continue to aggregate, as long as the mixture is above its T.sub.g, until 
complete phase separation occurs. 
The graft plant parts, however, form microdomains of individually dispersed 
fibers, filaments or molecular aggregates. When molecular aggregates form, 
they are thermodynamically stable and have dimensions of 100 micrometers 
or less. Commonly, these aggregates have at least one dimension, diameter 
or thickness, which is 5 micrometers or less, This property is of interest 
because the plant part both plasticizes the solid and separates out into a 
microphase which permeates and reinforces the plastic. The formation of 
this separated solid is controlled by the composition of the reaction 
mixture used to make the copolymer and the molecular size of the product. 
The existence of these structured solids can be verified by measurements 
of the glass transition temperature of the new solids. Samples of 5 to 10 
mg of reaction product were heated at 10.degree. C. per minute in a 
differential scanning calorimeter to monitor heat capacity as a function 
of temperature. Studies on metal alloys have shown that internally 
structured solids have two glass transitions, with the temperature of each 
transition produced by the composition of each phase. This same phenomenon 
is seen in these grafted plant pads, as shown by the data of Table 15. The 
structures which can form within these cooled solids are small spheres of 
plant part in a plastic phase, small threads of plant part in a plastic 
phase, hexagonally arrayed threads of plant part in plastic phase, thin 
layers of plant part separated from one another by thin layers of plastic, 
and each of the previous list of structures with the plant part and 
plastic phases exchanged in position. The labels "thin" and "small" mean 
100 .mu.m or less. The small dimension of the spheres and cylinders is 
normally the diameter while the small dimension for the layered structure 
is normally the layer thickness. Illustrations of the structures suggested 
by the differential scanning calorimetry data and the microemulsion data 
are given as FIGS. 3, 4, and 5. 
These new, internally structured solids are extremely useful since they 
constitute self-forming composites, materials with a rheology controlled 
by internal structure, sound dampening materials, and substances with 
directionally anisotropic physical properties. Such substances, with 
tensile strength, impact strength, ductility, malleability, conductivity, 
absorbance, and dampening which depend on orientation of the solid, have 
extremely functional uses in smart materials and new products. Electron 
micrographs of plant parts grafted with electron absorbing monomers (Table 
16, example 89) show distinct plant and plastic phases in the copolymer. 
See FIG. 7. 
These new grafted products can be blended with other reagents and heat 
treated or formed to make novel, highly functional articles. Of particular 
importance is the foam that can be formed from these plant part plastics. 
Foam is used to mean cellular polymer, foamed plastic, expanded plastic, 
and plastic foam, all common labels in use. The foam is a two-phase, 
gas-solid material in which the solid is continuous and at least partially 
composed of the grafted composition of this disclosure. "Cells" are the 
gas phase in the foam. If the cells are discrete such that the gas phase 
of each is independent of that of the other cells, the foam is termed 
closed-cell. The foams of this disclosure are usually closed cell. At gas 
volumes less that 70 to 80 percent of total volume, the cells are 
spherical or ellipsoidal while at larger gas volumes the cells become 
packed, regular dodecahedra. The cells are usually 1 cm or less in 
diameter with 1 mm or less a preferred diameter. The cells contain blowing 
agent, air, or other gases generated during foaming. The solid contains 
the grafted composition of this disclosure, other plastics or polymers, 
fillers, extenders, nucleating agents, stabilizers, crosslinkers, and 
conditioning agents. 
TABLE 15 
__________________________________________________________________________ 
Differential Scanning Calorimetry Data For Lignin, 
Poly(1-phenylethylene), and Graft Copolymer. 
Lig. % 
Lig. % 
Sample in in Ramp 
Number Reaction 
A Peak(s, .degree.C.) 
.degree.C./min. 
Material 
__________________________________________________________________________ 
Amoco RIPO 
0 0 102.6 10 pure poly(1-phenylethylene) 
30-95-1 LIG 
100.0 
100.0 
116.17 10 pure lignin 
35-102-4BB 
100.0 
100.0 
150.82 10 blank reaction lignin 
30-100-4A (31) 
9.6 10.32 
94.82 
(114.62)* 
10 Copolymer 
35-130-3A (33) 
22.0 27.32 
98.43 
(133.97)* 
10 Copolymer 
35-110-3A (28) 
30.0 32.17 
98.23 
(124.10)** 
10 Copolymer 
35-120-2A# (30) 
30.0 34.49 
102.35 
(144.48)** 
20 Copolymer 
35-113-3A (32) 
30.0 32.30 
95.73 
133.25 
10 Copolymer 
35-105-3A (34) 
46.0 50.53 
94.11 
125.12 
10 Copolymer 
35-120-3A# (29) 
46.0 51.84 
101.63 
143.27 
20 Copolymer 
__________________________________________________________________________ 
#1134-4 lignin was used. 
*very small peak 
**small peak 
Foams are formed by increasing internal pressure of a gas phase or by 
decreasing external pressure on the solid. Internal pressure to form a 
foam is usually increased by a blowing agent. Typical blowing agents are 
isomeric pentanes and hexanes, halocarbons, C.sub.1 to C.sub.8 
hydrocarbons, air, carbon dioxide, water, nitrogen, noble gases, and 
chemicals which release a gas such as sodium citrate-sodium hydrogen 
carbonate or water-isocyante. Blowing agents represent 0.5 to 25 weight 
percent of the formulation with 2 weight percent being a usual value. The 
grafted composition can be polymerized in the presence of a blowing agent 
but it is preferred that the grafted composition and blowing agent be 
heated and blended together. After forming and cooling under pressure, the 
grafted composition-blowing agent mixture is an expandable particle. The 
expandable particles are converted to foam in two steps. First, the 
particles are expanded by steam, hot air or hot water to make prefoamed 
beads and then the aged prefoamed beads are placed in a mold and heated 
again. This melds the prefoamed beads into a single piece. 
When all or part of an additive volatilizes within these new thermoplastics 
while the plastic is above its glass transition temperature, the surface 
tension of the plastic and its high viscosity keep the bubble inside the 
melt, producing a cavitated, porous solid as the plastic cools. These 
solids with extensive, microporous structure and a low density can be 
intentionally formed to take advantage of the very low thermal 
conductivity of the multicellular solid created. These materials can be 
used as insulating filling in refrigerators; solid, hard panels to replace 
soft, crushable insulation like glass wool in houses; and, most preferred, 
as disposable, insulating packaging. The plastic foams have hard, 
contiguous surfaces which maintain substances on their surface while 
having very low heat transfer rates though the foam. Thus, hot objects 
packaged in this foam stay hot for long periods with the duration of 
temperature maintenance increasing with increasing thickness of the foam. 
Since moisture and gasses do not pass through the foam, the contents of 
the packaged object stay inside the package. Of particular importance, 
however, is the unique ability of this foam to degrade completely in both 
its backbone content and sidechain content when the foam is exposed to the 
normal conditions of the forest floor. 
These materials are compostable and will degrade completely in moist air 
and contact with soil by degradation and digestion by white rot fungi. 
Products of starch, cellulose, and poly(hydroxybutric acid) blended into a 
synthetic polymer show appreciable biodegradability of the naturally 
occurring fraction of the plastic mixture but are not completely 
compostable. The synthetic polymer in these blends does not degrade. 
Lignin copolymers, in contrast, have the amazing property of being 
completely compostable. White rot Basidiomycete were able to compost 
1-phenylethene graff copolymers of lignin containing different proportions 
of lignin and sidechain. The composting tests were run on products which 
contained 10.3, 32.2, and 50.4 weight percent of lignin, respectively. The 
polymer samples were incubated with white rot Pleurotus ostreatus, 
Phanerochaete chrysosporium, Trametes versicolor, and brown rot 
Gleophyllum trabeum. White rot fungi degraded both components of the 
plastic samples at a rate which increased with increasing lignin content 
in the copolymer sample. Observation by scanning electron microscopy of 
incubated copolymers showed a deterioration of the plastic surface. Brown 
rot fungus did not affect any of these plastics nor did any of the fungi 
degrade any of the pure poly(1-phenylethylene). White rot fungi in liquid 
media produced and secreted oxidative enzymes associated with lignin 
degradation during incubation with lignin-poly(1-phenylethylene) 
copolymer. The enzymes measured were lignin peroxidase, laccase, and 
Mn(II) peroxidase. The timing of enzyme production was the same for fungi 
cultivated on lignin and on copolymer, indicating that the two materials 
were equivalent substrates. Fourier transform, infrared spectra of the 
copolymers incubated with white rot fungi show decreases of intensity in 
the whole range of absorbances characteristic of both lignin and 
poly(1-phenylethylene), thus showing loss of both components from the 
thermoplastic. All of the fungi overgrew the tested lignin powder but 
mycelia of the white rot fungi produced capsular material outside the 
hyphae. The adhesion of microorganisms to surfaces is a decisive step in 
microbially induced corrosion. Presumably the active colonizers of polymer 
are able to adhere due to their ability to produce exocellular polymers 
composed primarily of nonionic and anionic polysaccharides. All tested 
white rot fungi demonstrated an ability to decrease the weight of both 
constituents of copolymer, no matter what ratio of the main components, 
poly(1-phenylethylene) and lignin, the plastic contained. This is shown in 
FIGS. 6A, 6B, 6C, and 6D. These white rot Basidiomycete caused a range of 
weight loss of copolymer that varied with the fungus with which the 
plastic was inoculated. The decomposing activity of P. chrysosporium and 
T. versicolor exceeded the activity of P. ostreatus. Decomposition of 
copolymer by brown rot G. trabeum and pure poly(1-phenylethylene) by all 
tested fungi was insignificant. The most efficient degradation of both 
constituents of copolymer by white rot fungi was observed with the 
plastics containing 50.4 and 32.2 weight percent lignin, respectively. 
There was a greater weight loss of poly(1-phenylethylene) from copolymer 
with a greater concentration of lignin. Note that measured weight loss of 
the copolymer components is due to their mineralization (conversion to 
CO.sub.2 and H.sub.2 O) as well as their modification followed by 
ingestion by the fungal plant or partial solubilization in the surrounding 
medium. 
This capacity to degrade is particularly important for applications of 
these new materials to the slow release of substituents into the 
environment. Research by Nelson (Nelson, L. L., Entomological Special 
Studies, No. 31-004-71, AD72034, No. 1-006-71, AD729343, No. 31-014-071, 
AD729344, 1970) clearly shows that non-degradable carriers for bioactive 
materials retain significant amounts of the biologically active agent long 
after effective release has ceased. This environmental contamination will 
not longer be allowed in most developed countries. As the new grafted 
product degrades, any compounds contained in the copolymer and portions of 
the sidechain and the backbone are released into the area around the 
degrading material, as well as into the organism performing the 
degradation. The above discussion of composting, now studied on copolymers 
made with different monomers, shows that modification, ingestion, and 
release all occur during graft degradation. These data show that the 
copolymers are matrix, controlled release materials. An formulation of 
copolymer reacted with or blended with a biologically active compound, BA, 
can be formed into an object which will be an erodible device for the 
release of BA. Further, the copolymer of this invention forms an novel and 
uniquely functional material for the formation of such a device. The 
grafted plant is a cellular material which contains voids that can retain 
a biologically active compound. These same backbone materials, the 
vascular plant or its structural constituents, have hydroxyl, carboxyl, 
aromatic, and alkene functional groups that can react with a precursor, B, 
of a biologically active molecule. Once B is chemically bound to the plant 
part, the sidechain composition and molecular weight can be chosen to 
insure solubility, suspendability, or durability of the new product in the 
desired controlled release application. Upon degradation, B--R.sup.1 is 
released into the environment to affect an appropriate response from a 
target material or species. The adduct, --R.sup.1, is a functional group 
added to B during the degradation of the formulation. The material 
released, BA or B--R.sup.1, may be a biocide, herbicide, pesticide, growth 
stimulator or inhibitor, pH control agent, soil stabilizing agent, soil 
aerating agent, pheromone, repellent, or other biologically active agent. 
The adducts placed on B during degradation, --R.sup.1, can be hydrogen, H; 
hydroxyl, O--H; carboxyl, CO.sub.2 ; methyl, CH.sub.3 ; methoxyl, 
O--CH.sub.3 ; or ether, --O--. Hydroxyl and carboxyl groups are added 
routinely when esterase enzymes are active in the release of B. Methyl 
groups are often added by organisms to neutralize a toxin. Hydrogen, 
methoxyl, or ether groups are can be added by free radical recombination 
or by enzymatic action. It is important that the rate of release be zero 
order for many applications. A zero order rate is a release of a constant 
number of moles of biologically active agent in a given time. It is 
obtained by forming the formulated object as a high surface to volume 
piece, such as a flat sheet. The magnitude of the amount released in a 
given time, BA] or [B-R.sup.1 ], can be controlled by the sidechain, the 
concentration of biologically active agent inside the formulated object 
and the environment in which the object is distributed, but the rate of 
release is controlled by shape more than anything else. 
An example of such a controlled release material would be a grafted plant 
part designed to control floating weeds such as water hyacinth. This 
carrier of the herbicide should float to release the herbicide near the 
target species. The materials of this disclosure are novel in that any 
formulation with a volume fraction of plant, VF.sub.p, that satisfies the 
equation 
EQU VF.sub.p * 0.4+VF.sub.s * .rho..sub.s &lt;1.0 (6) 
will float. Here, VF.sub.s is the volume fraction of sidechain, .rho..sub.s 
is the density of the sidechain, and VF.sub.p +VF.sub.s =1.00. Because 
these copolymers have such a novel, low density, they can be formulated 
into materials which specifically deliver the herbicide, BA or B--R.sup.1, 
to the desired target. Further, the sidechain can be designed to allow the 
backbone to degrade at a controlled rate by controlling the hydrophilic or 
hydrophobic nature of the surface of the erodible object formed from the 
copolmer-BA or B--R.sup.1 product. A graft copolymer of a vascular plant 
and 2-oxo-3-oxypent-4-ene with a controlled degree of hydrolysis, 
##STR23## 
will allow the copolymer to degrade at a rate which increases as the ratio 
of m to n increases. 
Materials made with a biochemically active side group, B, on the sidechain 
or materials made from a backbone to which a functional adduct, B, has 
been attached can release this group or adduct all during the degradation 
of the material. By polymerizing a monomer, 
##STR24## 
onto the plant part which can release B--R.sup.1 as the degradation 
proceeds, a means is developed to produce, under natural conditions, a 
continuous and steady supply of B--R.sup.1. Usual duration of release of 
the side group is 10 to 150 days with shorter and longer times possible by 
controlling "B" or "BA" concentration in the new product, lignin content 
of the product, molecular weight of the sidechain, and the monomer mixture 
in the sidechain. Thus, sidechains with 2-propenoic acid repeat units will 
tend to make the product more soluble and mobile in the environment and 
increase its rate of decay. Sidechains with 1-phenylethene, 2-propene 
nitrile, or 2-oxy-3-oxo-4-methylpent-4-ene repeat units in them will make 
the new product more inert, slower to decay, and slower to release the 
adduct into the environment. These highly hydrophobic sidechains in high 
concentration and high molecular weight can slow the 10 to 150 day 
disintegration time to 1 to 2 years. The B groups are usually connected to 
the sidechain by carbon-carbon bonds while the B adducts are usually 
incorporated into the backbone by ester or ether linkages. Typical groups 
or adducts are acids, alcohols, alkanes, alkenes, alkoxides, amides, 
aromatics, cycloalkanes, esters, halogens, nitrile, and phenol groups and 
such groups further substituted with one or more groups. 
The vascular plant material upon which grafting takes place can be any 
substance of which lignin is a part, with wood being the most common 
example. In view of the complex nature of wood and the number of compounds 
that can obstruct a free-radical reaction, it is amazing but now proven 
that this chemistry will graft contiguous wood as well as free, extracted 
lignin. The data of Table 16 show that the polymerization occurs when wood 
is used as the lignin-containing material but does not occur when cotton; 
a lignin-free, cellulose-based, plant product; is used in the reaction. 
Further, extraction of the reaction products with benzene for between 2 
and 4.25 days shows that the wood has undergone a permanent, 50 to 375 
weight percent gain in mass due to grafted sidechains being attached to 
the wood. These reactions were all stirred at a rate of 4 Hz. Further 
reactions have been run on parts of a number of vascular plants. 
The reaction products of wood pulp and 1-phenylethene, and the reaction 
products of wood pulp and 4-methyl-2-oxy-3-oxopent-4-ene have been 
thermally compressed into thermoplastic composites which have good 
mechanical and thermal properties. The nature of the alteration of the 
plant is observed with reference to a plant part grafted with the monomer 
(4-bromophenyl)ethene [2039-82-9]. The bromine in this monomer allows the 
synthetic sidechain to absorb electrons far more intensely than the plant 
part. A thin section of an epoxy embedded plant shows that the surface of 
the plant part has been grafted with the bromine monomer in a reaction 
similar to that of sample 40-50-4, example 89, Table 16. The skin of the 
plant part, which has partially peeled off the plant, has a high 
concentration of bromine added by grafting. This is evident by both the 
darkness of the skin and a bromine map performed by the electron 
microscope. Photos were taken after benzene extraction of the product to 
remove homopolymer, so the coating is chemically bound. This bound plastic 
is the reason that composites and surface activity are possible with these 
new materials. 
TABLE 16 
__________________________________________________________________________ 
Copolymerization Reactions of Wood Pulp and 1-Phenylethene. 
Reactants (g) Type of Lignin - 
Sample 
1-Phenyl 
Wood H.sub.2 O.sub.2 
Yield Containing 
Number 
ethene 
Material 
CaCl.sub.2 
(mL) 
Solvent 
(g)/(wt. %) 
Material 
__________________________________________________________________________ 
40-14-5(82).sup.a 
18.06 
2.01 2.04 
3.0 40.00 
6.98/34.78 
RefineMech.Pulp 
40-26-5(83) 
11.37 
2.02 2.03 
3.0 50.04 
11.33/84.62 
MechanicalPulp 
40-32-4(84) 
8.08 2.00 2.00 
3.0 50.03 
7.54/74.80 
ThermomechPulp 
40-34-3(85) 
6.04 2.03 2.01 
3.0 50.07 
6.15/76.21 
VeryHighYidSulf 
40-36-2(86) 
4.64 2.04 2.06 
3.0 50.06 
5.14/77.41 
ChemTherMePulp 
40-38-1(87) 
3.59 2.00 2.05 
3.0 50.08 
3.84/68.69 
GroundWoodPulp 
40-106- 
8.05.sup.b 
1.00 3.02 
3.0 50.05 
0.91/0.00 
Cotton 
4(88) 
40-50-4(89) 
11.78.sup.c 
2.02 2.05 
3.0 50.02 
12.73/92.25 
GroundWoodPulp 
40-50-5(90) 
18.05.sup.d 
2.00 2.02 
3.0 50.10 
18.09/90.22 
GroundWoodPulp 
40-95-3(91) 
14.04 
6.01 3.00 
3.0 30.01 
19.84/98.95 
Oak Veneer 
40-94-3(92) 
14.03 
6.00 3.01 
3.0 30.02 
13.25/66.15 
Maple Veneer 
40-127- 
18.02 
2.01 3.02 
3.0 50.vertline.03 
18.31/91.41 
Used Lumber 
3(93) 
__________________________________________________________________________ 
.sup.a Example Numbers in parentheses. 
.sup.b This is the reaction on Degreased Cotton. Only cotton recovered. 
.sup.c This sample was prepared using 1(4-bromophenyl)ethene as the 
monomer. 
.sup.d This sample was prepared using 1(4-chlorophenyl)ethene as the 
monomer. 
The structures of 1-(4-bromophenyl)ethene [2039-82-9] and 
1-(4-chlorophenyl)ethene [27755-63-1] mentioned in the footnotes of the 
table on grafting of plant pulp are shown below. 
##STR25## 
The oak and maple hardwood veneer, examples 91 and 92, was grafted and 
then extracted for 48 hours with benzene. It showed a permanent weight 
gain and a hydrophobic surface, proving that the plastic was permanently 
bound to the wood. The used lumber used in example 93 was recovered from 
houses demolished in Boston and converted to wood filament with an aspect 
ratio of over 100. Aspect ratio is the ratio of an objects length to its 
diameter. Reactions with this wood ran very rapidly and gave a permanent 
15 percent or more gain in weight. This material, with its plastic surface 
and high aspect ratio, would be a very good reinforcing fiber for a 
thermoplastic composite. The thermoplastic continuous phase would have to 
have a solubility parameter that was within 5 units of the solubility 
parameter of the plastic surface grafted to the wood. 
These copolymers can be used to form any plastic or solid object by 
injection molding, blow molding, extrusion, vacuum forming, compression 
molding, transfer molding, or sheet casting. Compression molding of 
samples from Table VII containing up to 50 weight percent wood pulp gave 
uniform, opalescent thermoplastic sheets. A compression molding of 
mixtures of wood pulp and poly(1phenylethylene) under identical conditions 
gave clumped, heterogeneous sheets. Thus, this grafting process is 
necessary to produce useful, uniform thermoplastic solids. As the fraction 
of wood in the 2 phase solid increases, the tensile strength of the 
wood-plastic solid increases toward 175 MPa and the compressive strength 
changes toward 43 MPa. The compressive strength of the 2 phase solid will 
be between 5 and 150 megapascals. 
A molecular weight would not used to describe a grafted piece of a vascular 
plant, since it contains several components that resist separation and 
measurement. A molecular weight can be calculated for reaction products 
made from the structural plant polymers, lignin, cellulose, and 
hemicellulose, that have been separated from the plant. The molecular 
weights of such copolymers are in the range of about 15,000 to about 
30,000,000 as determined by size exclusion chromatography using known 
techniques. Under the process conditions of the present invention already 
described, it is possible to obtain molecular weights of about 1,000 to 
300,000. Under these conditions, the polymer molecular weight is generally 
increased by increasing the ratio of moles of monomer to moles of 
hydroperoxide. The converse is true when diminishing the molecular weight. 
However, by utilizing another aspect of the present invention, it has now 
been found possible to greatly boost or increase the molecular weight of 
the growing polymer during polymerization by conducting the reaction 
essentially in a gelled state. 
Generally, the gelled state can be formed by essentially repeating the 
procedures already described for synthesizing the graft copolymer, but by 
reducing the amount of dimethylsulfoxide (DMSO) solvent by a factor of 
0.25 or more. In other words, instead of using about 30 mL of solvent for 
the reaction as described in the Examples, about 23 or less mL are used 
instead. It has been theorized that by conducting the polymerization 
reaction in the gelled state, the propagation reaction continues, while 
the termination reaction is greatly diminished. It is also possible that 
the higher concentration of backbone allows crosslinking in these lower 
solvent-content reactions. In general, the gelling occurs at room 
temperature with no heating being necessary. Reaction times are somewhat 
variable and on the order of from 1 to about 48 hours with reaction yields 
as high as 80 weight percent possible in about 10 hours. 
Although the polymerization reaction of the present invention is a 
free-radical polymerization, the scope of the present invention clearly 
extends the concept of gel-state reactions to other types of 
polymerization reactions such as anionic or cationic chain polymerization 
or step polymerizations. These copolymers can be used to form any plastic 
or solid object by extrusion, blow molding, sheet casting, or injection 
molding. 
Obviously, many modifications and variations of the present invention are 
possible in light of the above teachings. Therefore, within the scope of 
the appended claims, the present invention may be practiced otherwise than 
as specifically described.