Polymer blends compatibilized with reactive polymers extended with miscible nonreactive polymers

Thermoplastic polymer blends containing normally incompatible polymers prepared by incorporating into one polymer repeating units containing pendant cyclic iminoether groups to form a first reactive polymer and another reactive polymer having coreactive groups to form a second reactive polymer which is capable of reacting with said first reactive polymer to form linkages between the polymers wherein said blend is characterized by said first or second reactive polymer being blended or extended with miscible polymer(s) to form a reactive blend thereof.

BACKGROUND OF THE INVENTION 
This invention relates to a compatible blend of two or more normally 
incompatible polymers. More particularly, this invention relates to blends 
of a first reactive polymer or polymer blend containing pendant cyclic 
iminoether groups and another reactive polymer or polymer blend containing 
groups which react with cyclic iminoether groups to form linkages between 
the reactive polymers or polymer blends. The subject invention is 
characterized by having at least one of the reactive polymers extended 
with a miscible but nonreactive polymer or polymers to form a reactive 
blend thereof. 
It is often desirable to prepare blends of polymers which maximizes the 
desirable properties but minimizes the deficiencies of the component 
polymers. For example, monovinylidene aromatic polymers, such as 
polystyrene, have desirable properties such as being easily thermoformed 
and have good mechanical characteristics. However, such monovinylidene 
aromatic polymers have certain undesirable properties such as poor 
environmental stress crack resistance (ESCR). On the other hand, 
polyolefins such as polyethylene or polypropylene have relatively good 
ESCR and low temperature properties but are not as readily thermoformed as 
desired. It would be highly desirable to provide a blend of a 
monovinylidene aromatic polymer and other polyolefins which exhibits the 
desirable properties but not the deficiencies, of the component polymers. 
Similarly, it is often desirable to blend other polymers in like manner. 
Unfortunately, however, such blends often do not exhibit these expected 
properties. Many such blends exhibit properties which are, in fact, far 
worse than those of the component polymers due to an incompatibility of 
the polymers. For example, monovinylidene aromatic polymers such as 
polystyrene and rubber modified polystyrene are notably incompatible with 
many polymers which would otherwise be advantageously blended therewith. 
Thus, most blends containing polystyrene and like polymers exhibit poorer 
than expected properties. 
Various methods have been proposed to prepare blends of normally 
incompatible polymers. Generally, these methods have focused on the use of 
grafting techniques or the use of a third component, a compatiblizing 
agent, in the blend. For example, in U.S. Pat. Nos. 4,386,187 and 
4,386,188 it is taught to prepare blends of polyolefins and a polystyrene 
using a styrene/butadiene/styrene block copolymer. Compatibilizing agents 
which are ethylene/vinylacetate copolymers, ethylene/acrylic acid ester 
copolymers and ethylene/methacrylic acid ester copolymers have also been 
taught for use in preparing blends of polystyrene and polyolefins (see 
Japanese Patent Announcement Kokai No. 48-43031/1973). Other such 
compatibilizing agents are taught in, for example, U.S. Pat. Nos. 
4,188,432; 4,020,025; British Pat. No. 1,363,463 and German Pat. No. 
241,375. 
Unfortunately, these approaches to preparing compatible polymer blends 
often do not yield entirely satisfactory results. In many instances, the 
type and proportion of the component polymers which can be blended using 
these techniques is quite narrowly restricted. In addition, the inclusion 
of an additional component in the blend often has an adverse effect on the 
properties of the blend. However, the blend achieved is still not as 
compatible as desired and accordingly the properties of the blend are 
sometimes not as good as expected. 
Accordingly, it would be desirable to provide a blend of normally 
incompatible polymers in which improved compatibilization of the polymers 
and improved properties of the blend are achieved. It is further desirable 
to be able to maximize the type and proportion of the desirable component 
polymers in any particular blend. 
It has been discovered that in addition to reactive polymers which 
compatibilize normally incompatible polymers that unexpectedly these 
reactive polymers can be extended with miscible nonreactive polymers 
without a loss in blend compatibility. 
SUMMARY OF THE INVENTION 
In one aspect, the invention is a compatible blend of normally incompatible 
polymers. The blend of the invention comprises a first thermoplastic 
reactive polymer containing a compatibilizing amount of repeating units 
containing a pendant cyclic iminoether group and a second thermoplastic 
reactive polymer containing a compatibilizing amount of repeating units 
containing a coreactive group which is capable of reacting with said 
cyclic iminoether group to form a linkage between said first and second 
reactive polymer wherein said blend is characterized by said first and/or 
said second thermoplastic reactive polymer being extended with a 
respective miscible nonreactive polymer(s). Said first and second reactive 
polymer are normally incompatible when said first and second polymer do 
not contain such cyclic iminoether and coreactive groups. 
The blends of this invention are a compatible (or miscible) blend of the 
component polymers. Accordingly such a blend exhibits the desirable 
properties of each of the component polymers with no significant decrease 
in properties due to incompatibility. A significant advantage of this 
blend is that the amount of reactive polymers which are employed is 
reduced by extending them with miscible nonreactive polymers without 
decreasing the compatibility of the normally incompatible polymers. 
In addition, the blends of this invention can be prepared using wide ranges 
of reactive polymer components as well as a variety of other types of 
miscible polymer components. By varying the proportions of cyclic 
imino-ether and coreactive groups employed in the reactive polymers and by 
varying the type and amount of miscible nonreactive polymer blended with 
the respective reactive polymer, the properties of the resultant blend can 
be engineered to many desired end uses. Further, the increased flexibility 
in the amount of reactive polymers which need to be employed in the total 
blend can provide lightly crosslinked thermoplastic blends or highly 
crosslinked thermosetting blends of variable physical properties.

DETAIL DESCRIPTION OF THE INVENTION 
The term "blend" as employed herein refers to those solid mixtures of two 
or more polymers which are commonly referred to in the art as polymer 
blends or polymer alloys. The terms "compatible blend" or "miscible blend" 
and like terms, as employed herein, are not employed in the strict sense 
as meaning that the blend exhibits a single glass transition temperature, 
but instead is used to describe a blend which exhibits properties, 
especially physical properties, which are essentially intermediate to 
those of the component polymers, or better. By contrast, an "incompatible 
blend" or "immiscible blend" as used herein, refers to a blend which 
exhibits properties which are significantly poorer than those of the 
individual polymers. 
The subject blend or polymeric alloy generally comprises at least two 
"reactive polymers" which are not normally compatible. The "first reactive 
polymer" is functionalized with a cyclic iminoether group and the "second 
reactive polymer" is functionalized with a coreactive group that is 
capable of crosslinking with the cyclic iminoether group. At least one or, 
optionally, both of the reactive polymers are extended with miscible 
nonreactive polymer(s) to form a reactive blend thereof. The miscible 
nonreactive polymer can comprise the base polymer of the respective 
reactive polymer or any other polymer compatible with the reactive 
polymer. The reactive blends or reactive blend and reactive polymer may 
then be blended to form a new blend or alloy. For example, the cyclic 
iminoether functionalized polymer can be extended with a miscible 
nonreactive polymer to render that blend reactive. Likewise, the 
coreactive second polymer can be extended with polymers to produce a 
coreactive polymer blend. Subsequently, the iminoether functionalized 
blend can be reacted with the coreactive functionalized blend. 
The blends of this invention contain a first reactive polymer or polymer 
blend having pendant cyclic iminoether groups. Said cyclic iminoether 
groups are present in a compatibilizing amount, i.e., an amount which is 
at least sufficient to render the first reactive polymer or polymer blend 
compatible with the other polymer or polymer blend employed herein. Of 
course, the amount of cyclic iminoether group which is required to 
compatibilize the first reactive polymer blend depends somewhat on the 
particular polymers employed, the relative amount thereof present in the 
blend and the amount of coreactive groups on the second reactive polymer. 
However, in general, a compatibilizing amount of said cyclic iminoether 
group is present when the repeating units containing said cyclic 
iminoether group comprise at least about 0.01 weight percent of the first 
reactive polymer. 
Since, as described more fully hereinafter, the cyclic iminoether group 
apparently forms a linkage with the coreactive group on said second 
reactive polymer, it is readily seen that the degree of crosslinking and 
the molecular weight of the polymers of the blend can also be controlled 
with the proportion of cyclic iminoether and coreactive groups present in 
the blend. In fact, with control of the amounts of such groups in the 
blend, the blend of this invention can be prepared as desired to form a 
very lightly crosslinked thermoplastic blend or, conversely, a very highly 
crosslinked thermosetting material. However, it is only essential that the 
amount of cyclic iminoether group in said first reactive polymer and 
coreactive group on said second reactive polymer be sufficient to 
compatibilize themselves in the blend. Most typically, the first reactive 
polymer contains from about 0.01 to 10 in weight percent of repeating 
units containing pendant cyclic iminoether groups. More preferably, the 
first reactive polymer contains from about 0.1 to about 5 weight percent 
of such repeating units. 
The cyclic iminoether groups are advantageously described by the general 
structure 
##STR1## 
wherein each R is independently hydrogen, or an inertly substituted 
hydrocarbon containing 18 or fewer carbon atoms; and n is a number from 
about 1 to about 5. Said cyclic iminoether group can be attached to the 
polymer chains through any of the carbon atom in the ring. Preferably, the 
cyclic iminoether is a 2-iminoether, i.e., is attached to the polymer 
chain through the 2-carbon atom to yield a structure as represented as 
##STR2## 
wherein R and n are as defined hereinbefore. Preferably, each R is 
hydrogen or lower alkyl and n is 1, 2 or 3. Most preferably, each R is 
hydrogen, n is 2 and the cyclic iminoether is a 2-oxazoline group. By 
"inertly substituted" it is meant that the referenced group contains no 
functional group which interferes with the polymerization or curing of the 
oxazoline group. 
Polymers containing repeating units having pendant cyclic iminoether groups 
are advantageously prepared by the polymerization of a monomer mixture 
comprising an ethylenically unsaturated monomer containing a cyclic 
iminoether group. Preferably, such monomer is a 2-alkenyl-2-oxazoline 
wherein said alkenyl group contains from about 2 to about 8, preferably 2 
to 4 carbon atoms. Most preferably, said monomer is 
2-isopropenyl-2-oxazoline. 
The first reactive polymer is a polymer of any monomer which (a) can be 
modified to contain pendant cyclic iminoether groups, or (b) can be 
copolymerized with a monomer which contains or can be modified to contain 
pendant cyclic iminoether group. In the preferred embodiment, wherein an 
ethylenically unsaturated cyclic iminoether is employed as a monomer, the 
first reactive polymer is advantageously a polymer of an addition 
polymerizable monomer copolymerizable therewith. 
Said first reactive polymer is advantageously a polymer of a lower alkene, 
particularly a C.sub.1 -C.sub.8 alkene, more particularly, ethylene or 
propylene as well as copolymers thereof; a conjugated diene such as 
butadiene or isoprene as well as copolymers thereof; a vinylidene halide 
such as vinylidene chloride or copolymers thereof; vinyl acetate; an ether 
of an .alpha.,.beta.-ethylenically unsaturated carboxylic acid such as 
alkyl esters of acrylic or methyl acrylic acid and copolymers thereof; a 
monovinylidene aromatic compound such as styrene, vinyltoluene, t-butyl 
styrene, vinylnaphtalene and the like; as well as polymers of diverse 
other addition polymerizable monomers. Ethylenically unsaturated cyclic 
iminoethers, in particular 2-alkenyl-2-oxazolines, generally resemble 
styrene in their polymerization reactions. Accordingly, as a rule of 
thumb, polymers of monomers which are copolymerizable with styrene will 
generally be usefully employed herein. Due to the polymerization reactions 
of 2-alkenyl-2-oxazolines and the tendency for styrenic polymers to be 
incompatible with a wide range of other thermoplastic materials, it is 
preferred that the first polymer be a polymer of a 2-alkenyl-2-oxazoline 
and styrene, especially 2-isopropenyl-2-oxazoline and styrene. 
The coreactive group may be pendant on said second reactive polymer, may 
form terminal groups thereon or may be incorporated into the polymer 
backbone thereof. Polymers containing coreactive groups along the polymer 
backbone include, for example, polyamines, such as the diverse 
polyalkylene amines; and the like. Polymers containing terminal coreactive 
groups include, for example, diverse polysulfides (Thiokols), epoxy resins 
and polyalkylene glycols. 
Most generally, said second reactive contains pendant coreactive groups 
which are derived from an addition polymerizable monomer containing the 
desired coreactive group. Preferred, are polymers having repeating units 
derived from .alpha.,.beta.-ethylenically unsaturated monomers containing 
said coreactive groups. Examples of such polymers are polymers of 
unsaturated carboxylic acids such as acrylic acid, methacrylic acid, 
itaconic acid, maleic acid and the like; unsaturated amines such as 
vinylamine and the like. In addition, polymers of other monomers which can 
be chemically modified to form pendant coreactive groups in the polymers, 
such as acrylonitrile, are usefully employed herein. 
The second reactive polymer contains at least a sufficient amount of said 
coreactive groups to compatibilize itself with said first reactive 
polymer. As stated hereinbefore, a compatibilizing amount of said 
coreactive group will depend on the particular polymers employed in the 
blend as well as the relative proportions of said polymers in the blend 
and the amount of the iminoether groups present on said first reactive 
polymer. However, as with the iminoether group, a compatibilizing amount 
of the coreactive group is typically present when at least about 0.01 
weight percent of the repeating units of the second reactive polymer 
contain coreactive groups. When said coreactive group is an integral part 
of the structure of the polymer backbone, as many as 100 weight percent of 
such repeating units in the second reactive polymer may contain coreactive 
groups. Typically, when said coreactive group is a pendant group 
incorporated into said second reactive polymer for the primary purpose of 
compatibilizing the blends of this invention, it is preferred that the 
repeating units containing said coreactive groups comprise from about 0.01 
to about 10, more preferably, from about 0.1 to about 5 weight percent of 
said second reactive polymer. 
The second reactive polymer can be one of any thermoplastic polymer which 
contains or can be modified to contain a coreactive group as described 
hereinbefore. Addition polymers such as polymers of olefins, vinyl 
halides, vinylidiene halides, acrylic esters, monovinylidene aromatics and 
the like as described hereinbefore in conjunction with a description of 
said first reactive polymer are useful with said second reactive polymer. 
In order to be useful herein the second reactive polymer is generally a 
copolymer of an addition polymerizable monomer which contains said 
coreactive group or which can be modified subsequent to polymerization to 
impart said coreactive group thereto. For example, any of the 
aforementioned addition polymers can be copolymerized with an addition 
polymerizable carboxylic acid to impart carboxyl groups to the polymer. 
Amino groups, amide groups and like coreactive groups can be imparted to 
the second reactive polymer in similar manner by copolymerizing a monomer 
mixture containing the desired proportion of an addition polymerizable 
monomer containing such group. Also, graft or block copolymers wherein at 
least one of the grafted segments or blocks contain a reactive group can 
be employed herein. 
Polymers of certain monomers such as vinyl or vinylidene halide or 
acrylonitrile can be modified after the polymerization thereof to impart 
coreactive moieties thereto. For example, vinyl chloride can be reacted 
with ammonia or a primary amine to place pendant amine groups on the 
polymer. Similarly, acrylonitrile can be hydrogenated after its 
polymerization to form pendant amine groups. 
Certain other polymers which normally contain coreactive groups may be 
employed as the second reactive polymer. For example, polymers containing 
repeating amine linkages, such poly(ethyleneimine) or a partially 
hydrolyzed poly(2-alkyl-2-oxazoline) are suitable as the other polymer 
herein. Other suitable polymers include those which contain amine, 
carboxylic acid, hydroxyl, epoxy, mercaptan, anhydrate and like groups in 
the polymer chain or as end groups therein. 
When the second reactive polymer does not normally contain coreactive 
groups it is generally desirable to prepare the polymer with relatively 
small amounts of said coreactive groups. This is because it is usually 
desirable to minimize the effect of the coreactive group or monomers 
containing said coreactive group on the physical properties of the 
polymer. The presence of large amounts of certain reactive groups, such as 
acid groups, can cause the blend to have certain undesirable properties 
such as water-sensitivity, adhesion to mold and corrosion of molds. 
The blends of this invention are advantageously prepared from the component 
polymers and/or blend thereof by conventional melt blending or solution 
blending techniques. Melt blending is advantageously performed by heating 
each polymer to a temperature about its softening point and thoroughly 
mixing the softened polymers. Solution blending is performed by dissolving 
each component polymer into a common solvent and precipitating the 
dissolved polymers therefrom. Melt blending is the preferred method of 
preparing the blends of this invention. 
The order of blending the components of the subject blend can be critical. 
Generally, the reactive polymers and the miscible nonreactive polymers can 
be simultaneously blended to form the subject blend. However, where it is 
desirable to first form a preblend of the reactive polymers only the 
miscible nonreactive polymer which corresponds to the continuous phase of 
the preblend can be post-blended. This characteristic is the result of the 
reactive polymer which makes up the discontinuous phase not being able to 
a compatibilize its respective miscible nonreactive polymer due to the 
surrounding continuous phase which is composed of a noncompatible polymer 
which prevents the incorporation of the miscible polymer. On the contrary, 
the discontinuous phase does not prevent the extension of the continuous 
phase reactive polymer with its corresponding miscible nonreactive 
polymer. Preferably, the reactive polymers are either blended 
simultaneously with the miscible nonreactive polymers or preblended with 
their respective miscible nonreactive polymer. 
Preferably, the reactive polymer is extended with miscible nonreactive 
polymer in about a five to one weight ratio or less of nonreactive polymer 
to reactive polymer. Higher levels of nonreactive polymer can 
progressively deteriorate the blend properties. 
Nonreactive polymers that can be blended with the reactive polymers are 
those which are normally miscible (compatible) with either of the reactive 
polymers. For instance, reactive polystyrene (cyclic iminoether 
functionalized styrene) can be blended with polyphenylene oxide or a 
polystyrene; and a coreactive polymer such as ethylene acrylic acid can be 
pre-blended with a polyethylene. One preferred blend consists of reactive 
polystyrene and high impact polystyrene with ethylene acrylic acid and low 
density polyethylene. 
Although it is not intended to limit the invention to any theory, it is 
believed that the compatibility of the blends of this invention is due to 
the reaction of said coreactive and iminoether groups present therein. 
Said coreactive and iminoether groups are believed to react to form 
linkages between said first and second reactive polymer, thereby 
overcoming the normal tendency of these polymers to resist the formation 
of a compatible blend. 
Since crosslinkages between the polymers are present in the blends of this 
invention, it is apparent that presence of linking groups on each polymer 
can also be used as a control on the rheological and thermoplastic 
properties of the blends. Since the presence of such linking groups 
increase the molecular weight of the polymers in the blends, increasing 
the amounts of such linkages enables the practitioner to prepare more 
viscous, stronger materials by further increasing the amount of linkage in 
the blends. The blend can be converted into a thermosetting rather than a 
thermoplastic material. 
Typically the formation of said linkages is achieved by the application of 
a moderate amount of heat to the blends. The amount of heat required is 
typically dependent on the particular coreactive group employed. In 
general, carboxylic acid groups are more reactive than amide, amine or 
hydroxyl groups and therefore require lower temperatures to form such 
crosslinkages. Usually, when a hot blending technique is employed to form 
the blends, the temperature at which the melt blending is performed is 
generally sufficient to cause the formation of linkages therein. 
Generally, and especially when the coreactive group is a carboxylic acid, 
such linkages are formed in one minute or less at the temperatures used to 
melt blend the polymers. It may be desirable to incorporate into the blend 
a catalyst which increases the rate of the reaction between the iminoether 
and coreactive group. Lewis acids such as zinc chloride or iron chloride 
are suitable as such catalysts. In addition, it may be desirable to 
include a plasticizer or lubricant in the blends in order to facilitate 
the iminoether and coreactive groups contacting each other in the blending 
process. However, the inclusion of either a catalyst, plasticizer or 
lubricant is optional herein. An important advantage of the present 
invention is that the formation of links in the blends of this invention 
is accomplished without the formation of any by-products and without the 
formation of ionic links. Unlike most curable systems, in which water, 
ammonia, or alcohol or other condensation product is formed in the curing 
reaction, the formation of links in this invention does not create such 
by-products. Accordingly, the links are formed in these blends without the 
undesirable formation of vaporous condensation products and without 
introducing such condensation products as impurities in the blends. The 
use of ionic crosslinks is also undesirable because such ionic crosslinks 
are often sensitive to pH, water and electrolytes and render the blends 
somewhat hydrophilic. 
In one aspect, the properties of the blends can be adjusted by the amount 
and type of miscible nonreactive polymer blended with either of the 
reactive polymers. The cyclic iminoether functionalized or coreactive 
polymer can be effectively diluted to a desired level which will control 
the amount of potential crosslinking. This will also allow the use of less 
costly nonreactive polymers with reactive polymers to design more economic 
blends. 
The physical and chemical characteristics of the blends prepared with both 
reactive and nonreactive polymers are generally proportional to the amount 
of polymers employed in the blends. 
The process of extending the reactive polymers with compatible polymers can 
therefore be employed to improve the properties of the final blend. For 
example, where blending the reactive polymers resulted in a blend having a 
low melt flow rate either of the reactive polymers could be first extended 
with an appropriate polymer having a high melt flow rate such that the 
final blend had an acceptable flow rate. Therefore, the process of 
extending the reactive polymers allows the skilled artisan an opportunity 
to selectively engineer the final blend properties. 
The blends of this invention may be employed in most applications for which 
the component polymers are suitable. Said blends may be employed to form 
shaped articles of all types as well as for films for packaging and like 
usages. 
The following examples are provided to illustrate the invention but not to 
limit the scope thereof. All parts and percentages are by weight unless 
otherwise indicated. 
EXAMPLE I 
In a Brabender mixer heated to 280.degree. C. at 50 ppm was melt blended 
the polymer blends listed in Table I. The subject reactive blends were 
prepared by mixing the polyphenylene oxide (PPO) and 
polystyrene/2-isopropenyl-2-oxazoline (SIPO) copolymer containing 1 
percent by weight repeating 2-isopropenyl-2-oxazoline (IPO) units for 
approximately 3 minutes until a homogeneous blend was obtained. Similarly, 
the control blend was prepared by first blending the polyphenylene oxide 
and styrene until a homogeneous blend was obtained. To the first blends 
were then added ethylene acrylic acid (EAA) and allowed to mix for an 
additional 5 minutes. The torque measurements for blending the components 
were recorded and both blends were then compression molded and tested for 
melt flow rate, impact, and elongation. These measurements are recorded in 
Table I. 
EXAMPLE II 
Various polymeric alloys were prepared as in Example I. A comparison was 
made between unreactive polymer blends (Sample 3), the corresponding 
reactive polymer blends (Sample 4) and the effect of blending the miscible 
base polymer with the corresponding reactive polymer (Samples 5 and 6) as 
per the subject invention. The samples were prepared, compression molded 
and measured for melt flow rate, impact, elongation and tensile (Examples 
3-6 only). The results are shown in Table I. 
TABLE I 
__________________________________________________________________________ 
Polymer Blend Notched Torque 
(Percent Flow Izod Tensile 
Elongation 
After 
Sample* 
Weight Polymer) 
(G/10 min) 
Impact 
(psi) 
(percent) 
8 min 
__________________________________________________________________________ 
1 35 PPO/35 SIPO 
.06 1.28 -- 7.8 300 
(1% IPO) 
30 EAA 
2** 35 PPO/35 polystyrene 
.24 .55 -- 2.0 130 
30 EAA 
3** 50 polystyrene 
11.93 .61 1131 
1.7 -- 
50 LLDPE 
4** 50 SIPO (1% IPO) 
1.03 1.25 3425 
8.8 -- 
50 LLDPE (.44% MAH) 
5 50 SIPO (1% IPO) 
1.10 1.54 3866 
8.0 -- 
25 LLDPE (.88% MAH)/ 
25 LLDPE 
6 20 SIPO (2.5% IPO)/ 
1.05 1.42 3638 
13.2 -- 
30 Polystyrene 
25 LLDPE (.88% MAH) 
25 LLDPE 
__________________________________________________________________________ 
*Samples 1 and 2 are from Example I and Samples 3-6 are from Example II. 
**Not an example of the invention. 
PPO -- polyphenylene oxide; SIPO -- polystyrene/2isopropenyl-2-oxazoline; 
IPO -- 2isopropenyl-2-oxazoline; EAA -- ethylene acrylic acid; LLDPE -- 
linear low density polyethylene; MAH -- maleic anhydride. 
It is readily seen from the data presented in Table I that a compatible 
blend can be prepared from a miscible polymer blended with either reactive 
polymer (Samples 1, 5 and 6). Excellent physical properties are obtained 
with the blend of this invention in contrast to non-compatible blends of 
Samples 2 and 3 which generally exhibit poorer properties. 
In order to monitor the formation of linkages between the SIPO and EAA 
polymers, torque measurements were made for Example I while mixing the EAA 
and SIPO polymer in a Brabender as described hereinbefore. As a control 
(Sample 2), a torque measurement was made on a 35 PPO/35 Styrene/30 EAA 
blend. Upon adding the PPO/polystyrene blend to the softened EAA polymer, 
the torque exerted by the blend steadily decreased until a constant value 
of about 130 meter.grams was reached. The low torque value indicates that 
crosslinking did not occur between the PPO/styrene and EAA polymer. 
In like manner, the torque exerted by the 35 PPO/35 SIPO/30 EAA blend 
(Sample 1), was determined. The final torque exerted in preparing the 
blend was higher than that of the control (Sample 2), indicating the 
presence of crosslinking between the PPO/SIPO reactive blend and the EAA 
polymer. 
With respect to the results for Example II, it is seen that the physical 
properties of the reactive blends (Samples 5 and 6) are better than the 
comparative nonreactive blend (Sample 3). In addition, it is seen that 
Samples 5 and 6 which contained the miscible polymers preblended with the 
reactive polymers were not adversely affected from the inclusion of the 
miscible polymers in view of comparative Sample 4 which only contained 
reactive polymers.