Gel compositions comprising silica and functionalized carbon products

New gel compositions which comprise a carbonaceous component attached to a gel component. Preferably, the carbonaceous component is selected from the group consisting of: carbon blacks, carbon fibers, activated carbons and graphitic carbons; and the gel component is selected from the group consisting of: metal oxide gels and polymeric gels. .quadrature. Also disclosed are new gel compositions comprising: a gel component and a carbon black product having attached at least one organic group, the organic group comprising: a) at least one aromatic group, and b) at least one ionic group, at least one ionizable group, or a mixture of an ionic group and an ionizable group, wherein at least one aromatic group of the organic group is directly attached to the carbon black. Further disclosed are new gel compositions comprising: a gel component and a carbon black product having attached at least one organic group, the organic group comprising: a) at least one C.sub.1 -C.sub.12 alkyl group, and b) at least one ionic group, at least one ionizable group, or a mixture of an ionic group and an ionizable group, wherein at least one alkyl group of the organic group is directly attached to the carbon black. Uses for the gel compositions are also disclosed.

FIELD OF THE INVENTION 
The present invention relates to new gel compositions. 
BACKGROUND 
Gels and processes for producing them, are well known. As used herein the 
term "gel" encompasses aerogels, xerogels, hydrogels and other gels known 
in the art. The term "aerogel" was coined by S. S. Kistler in U.S. Pat. 
No. 2,188,007 and is generally utilized to refer to a gel which has been 
dried under supercritical temperature/pressure conditions. Gels, in 
particular aerogels, are utilized in a wide variety of applications, 
including thermal and acoustic insulation, catalyst supports and carriers, 
filters and molecular sieves and electronics. 
Gels having lower bulk densities are more advantageous for use in many 
applications. Because of their lower bulk densities, aerogels have become 
the gel of choice for many applications. However, as set forth above, 
aerogels are typically produced utilizing supercritical drying, which 
requires the use of relatively expensive processing equipment and 
conditions. 
It is also advantageous for certain applications, such as adsorbents to use 
gels having higher bulk densities. 
SUMMARY OF THE INVENTION 
The present invention provides a new gel composition which has improved 
performance properties in comparison with heretofore known gels. The gel 
composition of the present invention comprises: 
a carbonaceous component attached to a gel component. 
The carbonaceous component may be selected from the group consisting of: 
carbon blacks, carbon fibers, activated carbons and graphitic carbons 
attachable to a gel component. If necessary, the carbonaceous component 
may be modified so that the carbonaceous component will attach to the gel 
component of the gel composition of the present invention. Preferably, the 
carbonaceous component is chemically modified. 
The present invention also includes a new gel composition comprising: 
a gel component and 
a carbon black product having attached at least one organic group, the 
organic group comprising: a) at least one aromatic group, and b) at least 
one ionic group, at least one ionizable group, or a mixture of an ionic 
group and an ionizable group, wherein at least one aromatic group of the 
organic group is directly attached to the carbon black. Details relating 
to a process for preparing the carbon black product, and preferred 
embodiments of the new gel composition, are set forth in the following 
Detailed Description of the Invention Section. 
The present invention further includes a new gel composition comprising: 
a gel component and 
a carbon black product having attached at least one organic group, the 
organic group comprising: a) at least one C.sub.1 -C.sub.12 alkyl group, 
and b) at least one ionic group, at least one ionizable group, or a 
mixture of an ionic group and an ionizable group, wherein at least one 
alkyl group of the organic group is directly attached to the carbon black. 
Details relating to processes for preparing the carbon black product, and 
preferred embodiments of the new gel composition are set forth in the 
following Detailed Description of the Invention Section. 
Suitable gel components for use in the gel compositions of the present 
invention include metal oxide gels such as silica gels, titania gels, 
alumina gels and the like; and polymeric gels, such as 
resorcinol-formaldehyde (R--F) gels, melamine formaldehyde (M--F) gels, 
phenol-furfural (P--F) gels and the like. The preferred gel component is a 
metal oxide gel. 
The amount of carbonaceous component included in the gel compositions will 
depend on the intended end use of the gel composition. Generally, amounts 
of 1-99%, by weight of the carbonaceous component, may be utilized in the 
gel composition of the present invention. Where it is desirable to produce 
a gel composition having a lower bulk density, amounts of 1-50%, by 
weight, preferably 10-20%, by weight, of the carbonaceous component are 
utilized in the gel composition of the present invention. Alternatively, 
where it is desirable to produce a gel composition having a higher bulk 
density, amounts of 50-99%, by weight, preferably 75-85%, by weight, of 
the carbonaceous component are utilized in the gel composition of the 
present invention. As used herein, "bulk density" refers to the mass of a 
gel particle divided by the total volume of the particle. 
The gel compositions of the present invention may be advantageously 
utilized in applications known to those of ordinary skill in the art for 
gel compositions. In particular, the gel compositions of the present 
invention may be utilized in applications which include the following: 
Insulation, including thermal, electrical and acoustic insulation. 
Particulate Additives, including flatting agents, thickeners, fillers and 
reinforcing agents 
Adsorbents 
Catalyst Supports 
Membranes 
Filters 
Radiation Detectors 
Coatings, including heat resistant coatings 
Dielectrics, including low K dielectrics. 
Further details relating to the gel compositions of the present invention, 
their preparation and their uses are set forth in the following Detailed 
Description of the Invention section. The advantages of the gel 
compositions of the present invention will become apparent to those of 
ordinary skill in the art from the following more detailed description.

DETAILED DESCRIPTION OF THE INVENTION 
As set forth above, the gel composition of the present invention comprises: 
a carbonaceous component attached to a gel component. 
The accompanying scanning electron microscope photograph Figures are 
provided to illustrate particular carbonaceous components attached to a 
gel component. 
FIG. 1 is a SEM of a fracture surface of a gel composition which does not 
include a carbonaceous component. 
FIG. 2 is a SEM of a fracture surface of a gel composition which includes a 
carbonaceous component which is not attached to the gel component. In 
contrast, FIG. 3 is a SEM of a fracture surface of a gel composition which 
includes a carbonaceous component which is attached to the gel component. 
A more detailed explanation of FIGS. 1-3, and an explanation of the 
remaining FIGS. 4-8, is set forth below in the Examples section. 
In addition, the Rub-off characteristics of gel compositions of the present 
invention, wherein the carbonaceous component is attached to the gel 
component, are lower than that of comparable gel compositions wherein the 
carbonaceous component is not attached to the gel component. Further 
details relating to Rub-off are set forth in the following Examples 
section. 
The carbonaceous component of the gel composition of the present invention 
may be selected from the group consisting of: carbon blacks attachable to 
a gel component, carbon fibers attachable to a gel component, activated 
carbons attachable to a gel component and graphitic carbons attachable to 
a gel component. Certain carbonaceous components will not become attached 
to a gel component unless modified. Preferably, the carbonaceous component 
is chemically modified in the following manner. 
An attachable carbonaceous component may be prepared by reacting a 
carbonaceous component with a diazonium salt in a liquid reaction medium 
to attach at least one organic group to the surface of the carbonaceous 
component. Preferred reaction media include water, any medium containing 
water, and any medium containing alcohol. Water is the most preferred 
medium. Modified carbonaceous components and various methods for their 
preparation are described in the U.S. patent application entitled 
"Reaction of Carbon Black with Diazonium Salts, Resultant Carbon Black 
Products and Their Uses," filed Dec. 15, 1994, and assigned Ser. No. 
08/356,660 the same day as the present application, and incorporated 
herein by reference. Modified carbonaceous components and various methods 
for their preparation are also described in the U.S. patent application 
entitled "Reaction of Carbon Materials With Diazonium Salts and Resultant 
Carbon Products" filed Dec. 15, 1994, and assigned Ser. No. 08/356,653, 
now U.S. Pat. No. 5,554,739 issued Sep. 10, 1996 the same day as the 
present application, and also incorporated herein by reference. 
A method of preparing attachable carbonaceous components, for use in the 
gel compositions of the present invention, is described in the following 
paragraph with reference to carbon black as the carbonaceous component. 
Similar methods could be performed to prepare attachable carbonaceous 
components other than carbon black. 
To prepare attachable carbon black, the diazonium salt need only be 
sufficiently stable to allow reaction with the carbon black. Thus, that 
reaction can be carried out with some diazonium salts otherwise considered 
to be unstable and subject to decomposition. Some decomposition processes 
may compete with the reaction between the carbon black and the diazonium 
salt and may reduce the total number of organic groups attached to the 
carbon black. Further, the reaction may be carried out at elevated 
temperatures where many diazonium salts may be susceptible to 
decomposition. Elevated temperatures may also advantageously increase the 
solubility of the diazonium salt in the reaction medium and improve its 
handling during the process. However, elevated temperatures may result in 
some loss of the diazonium salt due to other decomposition processes. 
The carbon black can be reacted with a diazonium salt when present as a 
dilute, easily stirred, aqueous slurry, or in the presence of the proper 
amount of water for carbon black pellet formation. If desired, carbon 
black pellets may be formed utilizing a conventional pelletizing 
technology. 
A preferred set of organic groups which may be attached to the carbon black 
are organic groups substituted with an ionic or an ionizable group as a 
functional group. An ionizable group is one which is capable of forming an 
ionic group in the medium of use. The ionic group may be an anionic group 
or a cationic group and the ionizable group may form an anion or a cation. 
Ionizable functional groups forming anions include, for example, acidic 
groups or salts of acidic groups. The organic groups, therefore, include 
groups derived from organic acids. Preferably, when it contains an 
ionizable group forming an anion, such an organic group has a) an aromatic 
group or a C.sub.1 -C.sub.12 alkyl group and b) at least one acidic group 
having a pKa of less than 11, or at least one salt of an acidic group 
having a pKa of less than 11, or a mixture of at least one acidic group 
having a pKa of less than 11 and at least one salt of an acidic group 
having a pKa of less than 11. The pKa of the acidic group refers to the 
pKa of the organic group as a whole, not just the acidic substituent. More 
preferably, the pKa is less than 10 and most preferably less than 9. 
Preferably, the aromatic group or the C.sub.1 -.sub.12 alkyl group of the 
organic group is directly attached to the carbon black. The aromatic group 
may be further substituted or unsubstituted, for example, with alkyl 
groups. The C.sub.1 -C.sub.12 alkyl group may be branched or unbranched 
and is preferably ethyl. More preferably, the organic group is a phenyl or 
a naphthyl group and the acidic group is a sulfonic acid group, a sulfinic 
acid group, a phosphonic acid group, or a carboxylic acid group. Examples 
include --COOH, --SO.sub.3 H and --PO.sub.3 H.sub.2, and their salts, for 
example --COONa, --COOK, --COO.sup.- NR.sub.4.sup.+, --SO.sub.3 Na, 
--HPO.sub.3 Na, --SO.sub.3.sup.- NR.sub.4.sup.+, and PO.sub.3 Na.sub.2, 
where R is an alkyl or phenyl group. Particularly preferred ionizable 
substituents are --COOH and --SO.sub.3 H and their sodium and potassium 
salts. 
Most preferably, the organic group is a substituted or unsubstituted 
sulfophenyl group or a salt thereof; a substituted or unsubstituted 
(polysulfo) phenyl group or a salt thereof; a substituted or unsubstituted 
sulfonaphthyl group or a salt thereof; or a substituted or unsubstituted 
(polysulfo) naphthyl group or a salt thereof. A preferred substituted 
sulfophenyl group is hydroxysulfophenyl group or a salt thereof. 
Specific organic groups having an ionizable functional group forming an 
anion are p-sulfophenyl, 4hydroxy-3-sulfophenyl, and 2-sulfoethyl. 
Amines represent examples of ionizable functional groups that form cationic 
groups and can be attached to the same organic groups as discussed above 
for the ionizable groups which form anions. For example, amines may be 
protonated to form ammonium groups in acidic media Preferably, an organic 
group having an amine substituent has a pKb of less than 5. Quaternary 
ammonium groups (--NR.sub.3.sup.+) and quaternary phosphonium groups 
(--PR.sub.3.sup.+) also represent examples of cationic groups and can be 
attached to the same organic groups as discussed above for the ionizable 
groups which form anions. Preferably, the organic group contains an 
aromatic group such as a phenyl or a naphthyl group and a quaternary 
ammonium or a quaternary phosphonium group. The aromatic group is 
preferably directly attached to the carbon black. Quaternized cyclic 
amines, and quaternized aromatic amines, can also be used as the organic 
group. Thus, N-substituted phyridinium compounds, such as 
N-methyl-pyridyl, can be used in this regard. 
An advantage of the carbon black products having an attached organic group 
substituted with an ionic or an ionizable group is that the carbon black 
products may have increased water dispersibility relative to the 
corresponding untreated carbon black. In general, water dispersibility of 
the carbon black products increases with the number of organic groups 
attached to the carbon black having an ionizable group or the number of 
ionizable groups attached to a given organic group. Thus, increasing the 
number of ionizable groups associated with the carbon black products 
should increase their water dispersibility and permits control of the 
water dispersibility to a desired level. It can be noted that the water 
dispersibility of carbon black products containing an amine as the organic 
group attached to the carbon black may be increased by acidifying the 
aqueous media. 
When water dispersible attachable carbon black products are prepared, it is 
preferred that the ionic or ionizable groups be ionized in the reaction 
medium. The resulting product solution or slurry may be used as is or 
diluted prior to use. Alternatively the carbon black products may be dried 
by techniques used for conventional carbon blacks. These techniques 
include, but are not limited to, drying in ovens and rotary kilns. 
Overdrying, however, may cause a loss in the degree of water 
dispersibility. In the event that the carbon black products above do not 
disperse in the aqueous vehicle as readily as desired, the carbon black 
products may be dispersed using conventionally known techniques such as 
milling or grinding. 
In contrast to conventional carbon black pigments, the chemically modified, 
attachable carbon black products are not difficult to disperse in an 
aqueous medium. The chemically modified, attachable carbon black products 
do not necessarily require a conventional milling process, nor are 
dispersants necessarily needed to attain a usable dispersion. Preferably 
the chemically modified, attachable carbon black products only require low 
shear stirring or mixing to readily disperse the pigment in water. 
Pellet formation from the attachable carbon black products is preferably 
performed using a conventional wet process, pin-pelletizing method. The 
resultant pellets are easily dispersed in water with minimal shear 
stirring or mixing, reducing or avoiding the need for milling or the use 
of a dispersant. 
The present invention also includes a new gel composition comprising: 
a gel component and 
a carbon black product having attached at least one organic group, the 
organic group comprising a) at least one aromatic group, and b) at least 
one ionic group, at least one ionizable group, or a mixture of an ionic 
group and an ionizable group, wherein at least one aromatic group of the 
organic group is directly attached to the carbon black. Preferably the 
ionic or ionizable group is selected from the group consisting of: a 
carboxylic acid or a salt thereof; a sulfonic acid or a salt thereof; and 
a quaternary ammonium salt. Preferably the organic group is selected from 
the group consisting of: a sulfophenyl group or a salt thereof; 
p-sulfophenyl or a salt thereof; and carboxyphenyl or a salt thereof. 
Carbon black products, suitable for use in the various embodiments of this 
gel composition of the present invention may be produced in the manner 
described above with reference to the creation of an attachable 
carbonaceous component. 
The present invention further includes a new gel composition comprising: 
a gel component and 
a carbon black product having attached at least one organic group, the 
organic group comprising a) at least one C.sub.1 -C.sub.12 alkyl group, 
and b) at least one ionic group, at least one ionizable group, or a 
mixture of an ionic group and an ionizable group, wherein at least one 
alkyl group of the organic group is directly attached to the carbon black 
Preferably the ionic or the ionizable group is selected from the group 
consisting of: an ethane sulfonic acid or a salt thereof. Carbon black 
products, suitable for use in the various embodiments of this gel 
composition of the present invention may also be produced in the manner 
described above with reference to the creation of an attachable 
carbonaceous component. 
The gel compositions of the present invention may be produced by any 
process known in the art for the preparation of gel compositions. For 
example, a gel composition of the present invention may be produced by the 
following method which relates to an alkoxide system: 
1) Dissolving a precursor of the desired gel component (an alkoxide in this 
example) in alcohol; 
2) Adding water to the solution so that the molar ratio of alkoxide to 
water is approximately 1; 
3) Adding an acid to the resulting solution so that the molar ratio of 
water to acid equals approximately 1:0.0007 to produce a sol; 
4) Adding a carbonaceous component to the sol; 
5) Adding a catalyst (generally an acid or a base) to start gelation of the 
sol; 
6) Aging the resulting gel in a mold for approximately 24 hours at 
50.degree. C.; 
7) Washing the resulting gel with water to replace the solvent component 
with water, and then aging the gel in water at elevated temperature (up to 
100.degree. C., preferably approximately 70.degree. C.) for up to 24 
hours; 
8) Washing the aged gel in solvent to bleed the water out and replace the 
water with solvent; 
9) Drying the resulting gel to form a gel composition of the present 
invention. 
Gel precursors, suitable for use in the gel composition of the present 
invention include, but are not limited to metal oxide gel precursors known 
in the art, such as: 
______________________________________ 
Metal Oxide 
Form(s) as Gel Precursor 
______________________________________ 
SiO.sub.2 Alkoxide, Sodium Si1icate, Colloidal 
TiO.sub.2 Alkoxide, Colloidal 
Al.sub.2 O.sub.3 
Alkoxides, Colloidal, Sodium Aluminate, Salts 
______________________________________ 
The choice of a particular precursor is made based on the type of gel 
desired. 
Further details relating to the process for making a gel composition of the 
present invention, and exemplary processes are set forth below in the 
Examples section. 
As set forth in the preceding section, the gel compositions of the present 
invention may be utilized for any application known for gel compositions. 
As will be recognized by those of ordinary skill in the art, whether a 
particular gel composition of the present invention is desirable for use 
in a particular application will depend on the characteristics of the gel 
composition, such as the amount of carbonaceous material incorporated into 
the composition and the bulk density of the composition. 
Exemplary uses for gel compositions of the present invention include, but 
are not limited to the following: 
Insulation Applications 
The gel compositions of the present invention may advantageously be 
utilized in thermal, electrical and/or acoustical insulation applications 
as set forth below. 
Thermal Insulation 
A gel composition of the present invention may be incorporated as loose 
fill material in thermal insulation. In addition, a gel composition of the 
present invention may also be combined with a material selected from group 
consisting of: calcium silicate, a mineral fiber, a metal oxide powder, a 
polymer foam, fiberglass, and the like and the combination incorporated 
into thermal insulation. Alternatively, a gel composition of the present 
invention may be utilized under vacuum in thermal insulation. 
Electrical Insulation 
A gel composition of the present invention may be incorporated into a 
polymer composition intended for use as electrical insulation. 
Acoustic Insulation 
A gel composition of the present invention may be incorporated as a loose 
fill material in acoustic insulation. Alternatively, a gel composition of 
the present invention may be combined with another material, such as 
cellulose, or polymer foam, and the combination incorporated as fill 
material in acoustic insulation. 
Particulate Additive Applications 
The gel compositions of the present invention may be used as particulate 
additives, such as thickeners, flatters, fillers or reinforcing agents. 
Examples of each include the following: 
Thickeners 
A gel composition of the present invention may be utilized as a thickener 
in pigment compositions and printing inks. Non-toxic gel compositions of 
the present invention may also be utilized as a thickener in food 
products. 
Flatters 
The term "flatter" of "flatting agent" refers to composition which will 
dull or flatten the finish of a paint, varnish or film. A gel composition 
of the present invention may be utilized as a flatter for lacquers, 
semi-gloss varnishes, enamels or vinyl films. 
Filler 
A gel composition of the present invention may be utilized as a filler in 
cements, adhesives and natural or synthetic rubber compositions. 
Reinforcing Agent 
A gel composition of the present invention may also be utilized as a 
reinforcing agent in polymer compositions, such as molded brake linings 
and in natural or synthetic rubber compositions. 
Adsorbent 
A gel composition of the present invention may be utilized as a material 
for liquid, gas or vapor adsorption. 
Catalyst Support 
A gel composition of the present invention may be utilized as a host 
support for powdered metal, or metal oxide catalytic materials. 
Membranes 
A gel composition of the present invention may be utilized as a material 
for selective liquid, gas or vapor separations. 
Filters 
A gel composition of the present invention may be utilized as a filtration 
material for particulates. 
Radiation Detectors 
A gel composition of the present invention may be utilized to detect 
radiation in a radiation detector such as a Cherenkov radiation detector. 
Heat Resistant Coating 
A gel composition of the present invention may be utilized, in thin film 
form, as a thermal barrier coating. 
Low K Dielectric 
A gel composition of the present invention may be utilized in dielectric 
materials, for example as a low dielectric constant material. 
As will be recognized by those of ordinary skill in the art from the 
foregoing list of applications, the gel compositions of the present 
invention may be utilized in many, if not all, of the applications which 
heretofore utilized conventional gel compositions. It will also be 
realized that the foregoing list is not an exhaustive list, but merely 
representative of the many potential uses for the gel compositions of the 
present invention. 
The effectiveness and advantages of various aspects and embodiments of the 
present invention will be further illustrated by the following examples 
wherein the following testing procedures were utilized. 
The nitrogen surface area (N.sub.2 SA) of the carbon blacks utilized in the 
examples, expressed as square meters per gram (m.sup.2 /g) was determined 
according to ASTM test procedure D3037 Method A. 
The dibutyl phthalate adsorption value (DBP) of the carbon blacks utilized 
in the examples, expressed as milliliters per 100 grams of carbon black 
(ml/100 g), was determined according to the procedure set forth in ASTM 
D2414. 
The average primary particle size of the carbon blacks utilized in the 
examples, expressed as nanometers (nm), was determined according to the 
procedure set forth in ASTM D3849. 
The scanning electron microscope (SEM) photographs were produced utilizing 
a Hitachi S570 Scanning Electron Microscope, produced and sold by Hitachi 
Corporation. Each of the SEM photographs was taken at a power setting of 
20 kilovolts, and a magnification of 25,000. 
The aqueous residue of modified and unmodified carbon blacks was determined 
by the following procedure. The carbon black (5 g) was shaken with 45 g of 
water for 5 minutes. The resulting dispersion was poured through a screen 
and rinsed with water until the washings were colorless. A 325 mesh screen 
was used unless indicated otherwise. After drying the screen, the weight 
of residue on the screen was determined and expressed as a percentage of 
the carbon black used in the test. 
The bulk density and rub-off of the gel compositions were determined by the 
following procedures: 
Bulk Density 
The gels were cast and formed in cylindrical molds. In all cases the 
cylindrical shape of the gel was preserved upon drying. The total gel 
volume was determined by physically measuring the dimensions of a dry gel. 
The bulk density was determined by weighing the dry gel and dividing by 
the geometric volume. In instances where a rod like geometry was not 
maintained or, as a verification of the above method, mercury displacement 
was employed. The bulk density of gel compositions measured by mercury 
displacement was carried out as follows. A clean empty glass cell is 
filled with mercury to a specific height and the cell is weighed. The 
mercury is then removed and the cell is cleaned again. Next, a dry gel 
sample of known weight is placed in the glass cell and mercury is added to 
the cell to the same specific height as before. the weight of the cell 
containing mercury and the sample is measured. The weight of mercury in 
both cases is then converted to a volume based on the density of mercury. 
The difference between the volume of mercury which fills an empty cell and 
the volume of mercury which fills the cell containing a sample is known as 
the displaced volume. Since mercury does not wet the sample this volume is 
equal to the total volume of the sample. The density is then determined by 
dividing the weight of the sample by the displaced volume. 
Rub-off 
The rub-off of the gel compositions were measured in the following manner. 
A dry gel of specific size (approximately 6 mm in diameter by 25 mm tall) 
was slid several times for 2-3 inches along its 25 mm length against a 
white cloth, using hand pressure. The relative extent of carbon deposition 
was then compared to a calibrated computer generated gray scale. The 
computer generates varying shades of gray and assigns numbers ranging from 
0 to 50 depending on the extent of gray. As the numbers increase from 0 to 
50, so does the relative extent of gray. After the gel was applied to the 
cloth, a visual comparison between the deposited carbon, and the computer 
chart was made, and a gray scale number assigned accordingly. Lower 
numbers correspond to less rub-off. The rub-off values in combination with 
the SEM photographs are used to determine whether the carbonaceous 
material is attached to the gel component. 
The following examples illustrate methods of modifying carbonaceous 
materials and the production of gel compositions, including gel 
compositions of the present invention, from an alkoxide precursor and a 
sodium silicate precursor. 
EXAMPLES 
Three carbon blacks, CB-A, CB-B and CB-C, were utilized in the following 
examples. The analytical properties of each of the carbon blacks, as 
determined by the procedures described above, were as shown in Table 1 
below: 
TABLE 1 
______________________________________ 
Carbon Black Analytical Properties 
Avg. Primary 
N.sub.2 SA DBP Particle Size 
Carbon Black 
(m.sup.2 /g) 
(ml/100 g) 
(nm) 
______________________________________ 
CB-A 24 132 130 
CB-B 230 70 16 
CB-C 560 120 16 
______________________________________ 
Modification of Carbonaceous Materials 
Examples 14 illustrate methods of modifying carbonaceous materials, in 
particular carbon blacks. These examples also set forth the procedures 
utilized to produce the modified carbon blacks, Modified CB-A, Modified 
CB-B, Phenolic CB-B and Modified CB-C utilized in the remaining examples. 
Example 1 
This example illustrates the preparation of a modified carbon black product 
utilizing the carbon black designated as CB-A in Table 1 above. 
Two hundred grams of CB-A was added to a solution of 10.1 g sulfanilic acid 
and 6.23 g of concentrated nitric acid in 21 g of water. A solution of 
4.87 g of NaNO.sub.2 in 10 g of water was added to the rapidly stirring 
mixture. 4-Sulfobenzenediazonium hydroxide inner salt is formed in situ, 
which reacts with the carbon black. After 15 minutes, the dispersion was 
dried in an oven at 125 C. 
The resulting carbon black product was designated "Modified CB-A" and is a 
carbon black having attached 4-C.sub.6 H.sub.4 SO.sub.3.sup.- groups. 
Example 2 
This example illustrates the preparation of a modified carbon black product 
utilizing the carbon black designated as CB-B in Table 1 above. 
A solution prepared from 36.2 g sulfanilic acid, 8.76 g NaOH and 162 g of 
water was cooled in ice. Twenty grams of NO.sub.2 was added with stirring 
and the resulting suspension was warmed to 75 C. and added without delay 
to a pelletizer containing 300 g of CB-B. After pelletizing for three 
minutes, 35 g of additional water was added. After pelletizing for two 
additional minutes, the product was removed from the pelletizer and dried 
in an oven at approximately 125.degree. C. The product had a 325 mesh 
residue of 0.14%, compared to 94% for the unreacted carbon black 
The resulting carbon black product was designated "Modified CB-B" and is a 
carbon black having attached 4-C.sub.6 H.sub.4 SO.sub.3.sup.- groups. 
Example 3 
This example illustrates the preparation of a different modified carbon 
black product, than Example 2, utilizing the carbon black designated as 
CB-B in Table 1 above. 
5Amino-2-hydroxybenzene sulfonic acid (1.89 g) was dissolved in 100 g of 
warm water, 10 g of CB-B was added and the mixture was cooled to room 
temperature. Concentrated HCl (1.18 g) was added and then a solution of 
0.85 g sodium nitrite in water was added, forming a diazonium salt in 
situ, which reacts with the carbon black. After stirring for 15 minutes, 
the resulting dispersion was dried in an oven at 125 C. The product had a 
325 mesh residue of 0.06%, compared to 94% for the unreacted carbon black. 
The resulting carbon black product was designated "Phenolic CB-B" and is a 
carbon black having attached 4,3-C.sub.6 H.sub.4 (OH)(SO.sub.3.sup.-) 
groups. 
Example 4 
This example illustrates the preparation of a modified carbon black product 
utilizing the carbon black designated as CB-C in Table 1 above. 
Two hundred grams of CB-C was mixed into 2.8 L of water. Sulfanilic acid 
(42.4 g) was dissolved into the stirring mixture, and then a cold solution 
of 25.5 g NO.sub.2 in 100 g of water was added with rapid stirring. 
4-Sulfobenzenediazonium hydroxide inner salt is formed in situ, which 
reacts with the carbon black. Bubbles were released. After stirring for 
one hour, 5 g of NO.sub.2 was introduced directly into the mixture. The 
dispersion was stirred for 15 minutes, left overnight and dried in an oven 
at 130.degree. C. 
The resulting carbon black product was designated "Modified CB-C" and is a 
carbon black having attached 4-C.sub.6 H.sub.4 SO.sub.3.sup.- groups. 
As illustrated in the following examples, the modified carbon blacks, 
Modified CB-A, Modified CB-B, Phenolic CB-B and Modified CB-C were 
attachable to a gel component and utilized to form gel compositions of the 
present invention. For comparison purposes, gel compositions were also 
prepared utilizing the unmodified carbon blacks, CB-A, CB-B and CB-C. 
Alkoxide Gel Precursor (Up to 50%. by Weight (Solids) Loading) Examples 
Examples 5-22 are directed to gels produced from an alkoxide precursor 
only, and with an amount, less than or equal to 50%, by weight (solids), 
of a carbonaceous component. 
Example 5 
A concentrated silica sol was prepared by mixing 61 ml (milliliters) of 
tetraethyl orthosilicate (98% pure), 61 ml of ethyl alcohol, 4.87 ml 
deionized water, and 0.2 ml of 1M hydrochloric acid in a 500 ml round 
bottom flask with vigorous stirring. The flask was placed in a heating 
mantle and the mixture refluxed with the aid of a condenser at 70.degree. 
C. for 2 hours. The resulting sol, which contained 15% SiO.sub.2 by 
weight, was cooled and stored at 5.degree. C. until use. 
Prior to gelation the sol was warmed to room temperature and the 
concentration was adjusted by dilution with ethyl alcohol such that the 
resulting mixture contained 11% SiO.sub.2 by weight. This was accomplished 
by combining 70% by volume original sol with 30% by volume ethyl alcohol. 
Gelation was initiated by addition of 0.5M NH.sub.4 OH in a volume ratio 
of 1:10 ammonia to sol. After the ammonia was added, the mixture was 
allowed to stir for 2-5 minutes and then cast into cylindrical tubes. 
Gelation occurred within 7-10 minutes. The gels were then sealed within 
the molds to prevent drying and aged at 50.degree. C. for 24 hours. After 
the initial aging the gels were removed from the mold, placed in sealed 
tubes containing deionized water and aged further at 70.degree. C. for an 
additional 24 hours. Upon removal from the oven the gels were rinsed 
several times with deionized water. 
The gels were then placed in sealed tubes containing acetone and allowed to 
exchange pore fluid (primarily water) for 10 hours at 50.degree. C. At the 
end of a 10 hour interval the gels were rinsed with acetone. This process 
was repeated a total of 3 times. After three such intervals a portion of 
the gels were then directly dried from acetone, first at 50.degree. C. for 
12 hours then at 140.degree. C. for an additional 12 hours. The resulting 
gels showed some shrinkage and each had a measured bulk density of 0.5-0.6 
g/cm.sup.3. 
The remaining gels were placed in sealed tubes containing heptane and 
allowed to exchange pore fluid for 10 hours at 50.degree. C. At the end of 
a 10 hour interval the gels were rinsed with heptane. This process was 
repeated three times. After three such intervals the gels were then 
directly dried from heptane, first at 70.degree. C. for 12 hours then at 
140.degree. C. for an additional 12 hours. These gels retained their 
cylindrical shapes with the least amount of shrinkage and each had a bulk 
density of 0.4-0.44 g/cm.sup.3. 
The bulk density and rub-off of representative samples of the gels dried in 
acetone and heptane were determined according to the procedures described 
herein. The results are provided in Tables 2 and 3 below. 
Example 6 
This example illustrates the production of gel compositions which contain 
an unmodified carbon black component, designated herein as "CB-A", having 
the analytical properties set forth in Table 1. 
In this example the steps from Example 5 were substantially repeated with 
one exception. Prior to initiating gel formation a specific amount of CB-A 
was added to the sol which had been diluted down with 70% by volume 
original sol and 30% by volume ethyl alcohol. The amount of added carbon 
black was calculated such that the total solids content remained the same, 
so that in effect the amount of added carbon black replaced an equivalent 
mass of silica. In this example the desired solids content is 11% just as 
in Example 5. Therefore, of that 11% solids, 95% consisted of silica and 
the remaining 5% solids was added as free carbon black. In order to keep 
the solids content the same, the sol was diluted with an appropriate 
amount of ethyl alcohol to account for the adjusted silica content. 
Once the relative ratios were determined the appropriate amount of carbon 
black was stirred into the sol for 5-10 minutes. CB-A was dispersed into 
the solution such that 5% of the total solids content was CB-A and the 
balance was silica. Gelation was initiated as in the previous example. The 
volume ratio used to promote gelation was maintained at 1:10 and the 
concentration of the base remained at 0.5M. 
As in the previous Example, the ammonia was added, the CB-A was dispersed 
with vigorous stirring for 2-5 minutes and then cast into cylindrical 
tubes. Gelation occurred within 8-12 minutes. The gels were then aged for 
24 hrs at 50.degree. C., then removed from the casts and aged another 24 
hours in deionized water at 70.degree. C. The gels were then solvent 
exchanged and dried as outlined in Example 5, from acetone and heptane. 
The bulk density and rub-off of representative samples of the gels dried in 
acetone and heptane were determined according to the procedures described 
herein. The results are provided in Tables 2 and 3 below. 
Examples 7-11 
The steps from Example 6 were repeated with the exception that the amount 
of CB-A was increased from 10 to 50% of the total solids, the balance 
being silica. The particular amount of carbon black utilized in each 
example, as a percentage of total solids, is shown in the Table below: 
______________________________________ 
Amount of Carbon Black (CB-A) 
Example % Total Solids 
______________________________________ 
7 10 
8 15 
9 20 
10 30 
11 50 
______________________________________ 
When the amount of CB-A varied from 10 to 20% the wet gels were noticeably 
stronger. For a given solvent, the dried gels demonstrated reduced 
shrinkage and lower bulk density as the CB-A content increased. One factor 
that was independent of the carbon black content was the rub-off 
characteristic of each of the dried gels. Upon handling a dried gel which 
contained CB-A, a significant amount of residual carbon black was 
deposited from the material onto the gloves with which they were handled 
and to the surrounding media. In addition, the attrition rate of carbon 
fines for the gels prepared with CB-A was substantial. The rub-off 
characteristics, and substantial attrition rates, of the gels indicate the 
presence of carbon black which was not attached to the gel component. 
The bulk density and rub-off of representative samples of the gels dried in 
acetone and heptane, from each example, were determined according to the 
procedures described herein. The results are provided in Tables 2 and 3 
below. 
Example 12 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
In this Example the procedures used in Examples 6-11 were substantially 
repeated with the exception that the gel compositions incorporated the 
Modified CB-A of Example 1. 
As in Example 6 the Modified CB-A was dispersed into the partially 
hydrolyzed silica solution such that 5% of the total solids content was 
Modified CB-A and the balance was silica. A set of gels were then prepared 
with the addition of ammonia, aged in the same manner as described 
earlier, solvent exchanged with acetone and heptane, and dried as outlined 
in Examples 7-11. 
The Modified CB-A was dispersed more easily and remained dispersed longer 
in terms of settling behavior than the unmodified CB-A. In the wet state 
the gels seemed stronger than those without carbon black and slightly 
stronger than gels containing unmodified CB-A. For a given solvent, 
however, the bulk density was lower for materials made using the Modified 
CB-A. More important was the observation that the rub-off behavior was 
significantly reduced indicating that the carbon black was actively 
incorporated in the gel network, and attached to the gel component. 
The bulk density and rub-off of representative samples of the gels dried in 
acetone and heptane were determined according to the procedures described 
herein. The results are provided in Tables 2 and 3 below. 
Examples 13-17 
These examples illustrate the production of gel compositions of the present 
invention which comprise a carbon black attached to a gel component. 
The steps from Example 12 were repeated with the exception that the amount 
of Modified CB-A was increased from 10 to 50% of the total solids, the 
balance being silica. The particular amount of carbon black utilized in 
each example, as a percentage of total solids, is shown in the Table 
below: 
______________________________________ 
Amount of Carbon Black (Modified CB-A) 
Example % Total Solids 
______________________________________ 
13 10 
14 15 
15 20 
16 30 
17 50 
______________________________________ 
When compared to gels produced with unmodified CB-A the dried gels of 
examples 13-17, incorporating Modified CB-A, demonstrated reduced 
shrinkage and lower bulk densities for a given solvent as the Modified 
CB-A content increased. In addition, for a given solvent and Modified CB-A 
content the wet gels were physically stronger and the dried gels had lower 
bulk densities as compared to gels prepared with the unmodified CB-A. 
Another distinguishing feature of the entire Modified CB-A gel series was a 
noticeable difference in the rub-off behavior. Upon handling the dry gels, 
a substantial reduction in residual carbon deposited on gloves and 
surrounding media was noted in comparison with the gel compositions 
produced with unmodified CB-A. The attrition rate of carbon fines for the 
gels prepared with Modified CB-A was also greatly diminished in comparison 
with the gels produced with unmodified CB-A. These results indicate that 
the Modified CB-A was attached to the gel component. 
The bulk density and rub-off of representative samples of the gels dried in 
acetone, and heptane, from each example, were determined according to the 
procedures described herein. The results are provided in Tables 2 and 3 
below. 
Example 18 
In this Example the procedures used in Examples 6-12 were substantially 
repeated utilizing a different carbon black, designated herein as "CB-B", 
having the analytical properties set forth in Table 1. 
As in the previous Examples, CB-B was dispersed into the partially 
hydrolyzed silica solution such that 15% of the total solids content was 
CB-B and the balance was silica. A set of gels were then prepared with the 
addition of ammonia, aged, solvent exchanged and dried as outlined in 
Example 5. 
The bulk density and rub-off of representative samples of the gels dried in 
acetone and heptane was determined according to the procedures described 
herein. The results are provided in Tables 2 and 3 below. 
Example 19 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
In this Example the procedures used in Example 18 were substantially 
repeated with the exception that the gel compositions incorporated the 
Modified CB-B of Example 2. 
As in the previous Examples the Modified CB-B was washed according to the 
established protocol and then dispersed into the partially hydrolyzed 
silica solution such that 15% of the total solids content was Modified 
CB-B and the balance was silica A set of gels were then prepared, aged in 
the same manner as described earlier, solvent exchanged with acetone and 
heptane, and dried as outlined in the previous Examples. 
The bulk density and rub-off of representative samples of the gels dried in 
acetone and heptane were determined according to the procedures described 
herein. The results are provided in Tables 2 and 3 below. 
Example 20 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
In this Example the procedures used in Example 19 were substantially 
repeated with the exception that the gel compositions incorporated the 
Phenolic CB-B of Example 3. 
As in the previous Examples, the Phenolic CB-B was washed and then 
dispersed into the partially hydrolyzed silica solution such that 15% of 
the total solids content was Phenolic CB-B and the balance was silica. A 
set of gels were then prepared with the addition of ammonia, solvent 
exchanged and dried as outlined in the prior examples. 
The bulk density and rub-off of representative samples of the gels dried in 
acetone and heptane were determined according to the procedures described 
herein. The results are provided in Tables 2 and 3 below. 
Example 21 
In this Example the procedures used in the previous Examples 5-21 were 
substantially repeated utilizing a different carbon black, designated 
herein as "CB-C", having the analytical properties set forth in Table 1. 
As in the previous Examples, the CB-C was dispersed into the partially 
hydrolyzed silica solution such that 15% of the total solids content was 
CB-C and the balance was silica. A set of gels were then prepared with the 
addition of ammonia, solvent exchanged and dried as outlined in the prior 
Examples. 
The bulk density and rub-off of representative samples of the gels dried in 
acetone and heptane were determined according to the procedures described 
herein. The results are provided in Tables 2 and 3 below. 
Example 22 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
In this Example the procedures used in Example 21 were substantially 
repeated with the exception that the gel compositions incorporated the 
Modified CB-C of Example 4. 
As in the previous Examples, the Modified CB-C was washed and then 
dispersed into the partially hydrolyzed silica solution such that 15% of 
the total solids content was Modified CB-C and the balance was silica. A 
set of gels were then prepared with the addition of ammonia, solvent 
exchanged and dried as outlined in the prior Examples. 
The bulk density and rub-off of representative samples of the gels dried in 
acetone and heptane were determined according to the procedures described 
herein. The results are provided in Tables 2 and 3 below. 
TABLE 2 
______________________________________ 
Alkoxide Precursor Gels (.ltoreq.50% Carbon) Dried in Acetone 
Carbon 
Black 
%, by Bulk 
Carbon weight Drying Density 
Rub 
Example 
Black (solids) Solvent 
(g/cm.sup.3) 
Off 
______________________________________ 
5 None None Acetone 
0.60 -- 
6 CB-A 5% Acetone 
0.55 17.5 
7 CB-A 10% Acetone 
0.45 23 
8 CB-A 15% Acetone 
0.48 35 
9 CB-A 20% Acetone 
0.43 40 
10 CB-A 30% Acetone 
0.49 35 
11 CB-A 50% Acetone 
0.51 45 
12 Modified CB-A 
5% Acetone 
0.45 7.5 
13 Modified CB-A 
10% Acetone 
0.43 15 
14 Modified CB-A 
15% Acetone 
0.38 15 
15 Modified CB-A 
20% Acetone 
0.38 25 
16 Modified CB-A 
30% Acetone 
0.42 25 
17 Modified CB-A 
50% Acetone 
0.47 30 
18 CB-B 15% Acetone 
0.45 25 
19 Modified CB-B 
15% Acetone 
0.44 15 
20 Phenolic CB-B 
15% Acetone 
0.35 10 
21 CB-C 15% Acetone 
0.38 35 
22 Modified CB-C 
15% Acetone 
0.37 15 
______________________________________ 
TABLE 3 
__________________________________________________________________________ 
Alkoxide Precursor Gels (.ltoreq.50% Carbon) Dried in Heptane 
Carbon 
Black 
%, by Bulk SEM 
Carbon weight 
Drying 
Density 
Rub FIG. 
Example 
Black (solids) 
Solvent 
(g/cm.sup.3) 
Off # 
__________________________________________________________________________ 
5 None None Heptane 
0.40 -- 1 
6 CB-A 5% Heptane 
0.38 15 -- 
7 CB-A 10% Heptane 
0.37 20 -- 
8 CB-A 15% Heptane 
0.31 30 2 
9 CB-A 20% Heptane 
0.34 40 -- 
10 CB-A 30% Heptane 
0.36 35 -- 
11 CB-A 50% Heptane 
0.41 45 -- 
12 Modified CB-A 
5% Heptane 
0.36 5 -- 
13 Modified CB-A 
10% Heptane 
0.34 15 -- 
14 Modified CB-A 
15% Heptane 
0.29 10 3 
15 Modified CB-A 
20% Heptane 
0.30 25 -- 
16 Modified CB-A 
30% Heptane 
0.31 20 -- 
17 Modified CB-A 
50% Heptane 
0.33 30 -- 
18 CB-B 15% Heptane 
0.36 25 4 
19 Modified CB-B 
15% Heptane 
0.31 10 5 
20 Phenolic CB-B 
15% Heptane 
0.26 5 6 
21 CB-C 15% Heptane 
0.31 30 7 
22 Modified CB-C 
15% Heptane 
0.30 10 8 
__________________________________________________________________________ 
SEM FIG. # = Scanning Electron Microscope Figure Number 
As shown by the SEM photographs, in particular FIG. 3 of the gel 
composition of the present invention of Example 14, FIG. 5 of the gel 
composition of the present invention of Example 19, FIG. 6 of the gel 
composition of the present invention of Example 20 and FIG. 8 of the gel 
composition of the present invention of Example 22, the modified carbon 
blacks are attached to the silica gel component in the gel compositions of 
the present invention. As illustrated in FIGS. 3, 5, 6 and 8, minimal 
amounts or none of the attached carbonaceous component (modified carbon 
black) appears as a distinct aggregate in fracture surface SEM's of these 
gel compositions. These results indicate that the modified carbon black is 
attached to the silica gel component in several places and that the silica 
to carbon black link is stronger than the silica to silica links in 
conventional gel compositions which do not include a carbonaceous 
component attached to the gel component. 
In contrast, as illustrated in FIGS. 2, 4 and 7, fracture surface SEM's of 
gel compositions which include a carbonaceous component which is not 
attached to the gel component, show distinct aggregates of the carbon 
black. In these gel compositions, the carbon black is not attached to the 
silica gel component. 
Sodium Silicate Gel Precursor (Up to 50%, by Weight (Solids) Loading) 
Examples 
Examples 23-28 are directed to gels produced from a sodium silicate 
precursor and less than or equal to 50%, by weight (solids), of a 
carbonaceous component. 
Example 23 
A silica stock solution was prepared by mixing commercially available 
sodium silicate (SiO.sub.2 /Na.sub.2 O molar ratio of 3.22:1) with 
deionized water in a volume ratio of 1.33:1 water to sodium silicate. The 
temperature of the mixture was maintained at 15.degree. C. with vigorous 
stirring in a jacketed beaker. A separate solution comprising 2M H.sub.2 
SO.sub.4 was prepared by diluting concentrated sulfuric acid (96%) with 
water. An aliquot of 104 ml of the sodium silicate stock solution was then 
slowly added to 50 ml of stirred 2M acid. The rate of silicate addition 
was kept constant at 1 ml/minute and the acid solution was maintained at 
15.degree. C. in a jacketed beaker. The resulting silica sol contained 
approximately 10 wt % silica in a salty solution. 
Gelation was accomplished by controlled addition of 1M NaOH until the pH of 
the sol reached 5. At this point the sol was vigorously stirred for 1 
minute and then cast into cylindrical tubes. Gelation occurred in 5 
minutes and the tubes were sealed to prevent drying. 
The gels were allowed to age for 1-2 hours at 50.degree. C. in the molds 
after which they were placed in sealed tubes containing deionized water 
and kept at room temperature. Fresh water was added every 3 hours for a 
total of 12 hours at which time it was determined (by insertion of a 
sodium electrode) that the sodium sulfate salt was completely removed from 
the gel. 
The gels were then aged at 70.degree. C. in deionized water for up to 24 
hours. Upon removal from the oven the gels were rinsed several times with 
deionized water, placed in sealed tubes with acetone and allowed to 
exchange pore fluid for 10 hours at 50.degree. C. At the end of 10 hours 
the gels were rinsed with acetone and stored in fresh acetone at 
50.degree. C. This procedure was repeated three times. 
After three such intervals, the gels were placed in sealed tubes containing 
heptane and allowed to exchange pore fluid for 10 hours. At the end of 10 
hours the gels were rinsed with heptane and stored in fresh heptane at 
50.degree. C. This procedure was repeated three times. 
After three such intervals, the gels were dried directly from heptane, 
first at 70.degree. C. for 12 hours then at 140.degree. C. for an 
additional 12 hours. The resulting dried gels retained their cylindrical 
forms and exhibited minimal shrinkage. 
The bulk density and rub-off of a representative sample of the gel 
compositions were determined according to the procedures described herein. 
The results are provided in Table 4 below. 
Example 24 
This example illustrates the production of gel compositions which contain 
an unmodified carbon black component, designated herein as "CB-A", having 
the analytical properties set forth in Table 1. 
The steps from Example 23 were substantially repeated with some processing 
changes. Prior to initiating gel formation a specific amount of a 
particular carbon black, CB-A (as in Examples 6-11) was added to the sol. 
The amount of added carbon black was calculated such that the total solids 
content remained the same, so that in effect the amount of added carbon 
black replaced an equivalent mass of silica. In this example, the desired 
solids content is 10%, just as in Example 23. Therefore, of the 10% 
solids, 90% consisted of silica and the remaining 10% solids were added as 
free carbon black (CB-A). In order to keep the solids content the same, 
the sol was diluted with an appropriate amount of deionized water to 
account for the adjusted silica content. 
Once the relative ratios were determined, the appropriate amount of carbon 
black was stirred into the sol for 5-10 minutes. In this example, CB-A was 
dispersed into the solution containing sodium silicate combined with 
sulfuric acid such that 10% of the total solids content was CB-A and the 
balance was silica. Gelation was initiated as in Example 23, by increasing 
pH with 1M NaOH to a final pH of 5. 
After gelation the materials were aged at 50.degree. C. for 1-2 hours, as 
in Example 23, removed from the molds, and then washed free of salt for 12 
hours at room temperature. The loaded gels were then solvent exchanged and 
dried as outlined in Example 23, from heptane. 
The bulk density and rub-off of a representative sample of the gel 
compositions were determined according to the procedures described herein. 
The results are provided in Table 4 below. 
Example 25 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
In this Example the procedures used in Example 24 were substantially 
repeated with the exception that the gel compositions incorporated the 
Modified CB-A of Example 1. 
The Modified CB-A was dispersed in a beaker of acetone, vacuum filtered, 
and then rinsed repeatedly with deionized water until the pH of the wash 
water was close to neutral. The Modified CB-A was then dried at 
140.degree. C. for 12 hours. 
As in Example 24 the Modified CB-A was dispersed into the solution 
containing sodium silicate combined with sulfuric acid such that 10% of 
the total solids content was Modified CB-A and the balance was silica. In 
contrast to unmodified CB-A, addition of Modified CB-A was limited due to 
the stability of the surface groups. Only at pH values greater than 3 
could Modified CB-A be introduced into the sol such that the surface 
modification could be preserved. Therefore, the pH was carefully raised to 
3 with controlled addition of 1M NaOH and the appropriate amount of 
Modified CB-A dispersed into the sol. Gelation was achieved, as before, by 
controlled addition of 1M NaOH until the pH of the sol reached 5. 
After gelation the materials were aged at 50.degree. C. for 1-2 hours as 
before, removed from the molds, and then washed free of salt for 12 hours 
at room temperature. The gel compositions were then aged up to 24 hours at 
70.degree. C. in deionized water. A portion of the gels were then solvent 
exchanged and dried from heptane as outlined in the prior Examples. 
The bulk density and rub-off of a representative sample of the gel 
compositions were determined according to the procedures described herein. 
The results are provided in Table 4 below. 
Example 26 
In this Example the procedures used in Example 24 were substantially 
repeated utilizing a different carbon black, designated herein as "CB-B", 
having the analytical properties set forth in Table 1. 
Prior to initiating gel formation a specific amount of CB-B (as above), was 
added to the sol. The amount of added CB-B was calculated such that the 
total solids content remained the same, so that in effect the amount of 
added CB-B replaced an equivalent mass of silica. In this example, the 
desired total solids content is 10% just as in Example 23. Therefore, of 
that 10% solids, 90% consisted of silica and the remaining 10% solids were 
added as free CB-B. In order to keep the solids content the same, the sol 
was diluted with an appropriate amount of deionized water to account for 
the adjusted silica content. 
Once the relative ratios were determined, the appropriate amount of carbon 
black was stirred into the sol for 5-10 minutes. In this example, CB-B was 
dispersed into the solution containing sodium silicate combined with 
sulfuric acid such that 10% of the total solids content was CB-B and the 
balance was silica. Gelation was initiated as in the previous examples by 
increasing pH with 1M NaOH to a final pH of 5. 
After gelation, the materials were aged at 50.degree. C. for 1-2 hours as 
before, removed from the molds and then washed free of salt for 12 hours 
at room temperature. The gel compositions were then aged up to 24 hours at 
70.degree. C. in deionized water. A portion of the gel compositions were 
then solvent exchanged and dried from heptane as outlined in the prior 
examples. 
The bulk density and rub-off of a representative sample of the gel 
compositions were determined according to the procedures described herein. 
The results are provided in Table 4 below. 
Example 27 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
In this Example the procedures used in Example 26 were substantially 
repeated with the exception that the gel compositions incorporated the 
Modified CB-B of Example 2. 
The Modified CB-B was dispersed in a beaker of acetone, vacuum filtered, 
and then rinsed repeatedly with deionized water until the pH of the wash 
water was close to neutral. The Modified CB-B was then dried at 
140.degree. C. for 12 hours. 
As in Example 24, the Modified CB-B was dispersed into the solution 
containing sodium silicate combined with sulfuric acid such that 10% of 
the total solids content was Modified CB-B and the balance was silica. In 
contrast to unmodified CB-B, addition of Modified CB-B was limited due to 
the stability of the surface groups. Only at pH greater than 3 could 
Modified CB-B be introduced into the sol such that the surface 
modification could be preserved. Therefore, the pH was carefully raised to 
3 with controlled addition of 1M NaOH and the appropriate amount of 
Modified CB-B dispersed into the sol. Gelation was achieved as before by 
controlled addition of 1M NaOH until the pH of the sol reached 5. 
After gelation, the materials were aged at 50.degree. C. for 1-2 hours as 
before, removed from the molds, and then washed free of salt for 12 hours 
at room temperature. The gel compositions were then aged up to 24 hours at 
70.degree. C. in deionized water. The gels were then solvent exchanged and 
dried from heptane as outlined in the prior Examples. 
The bulk density and rub-off of a representative sample of the gel 
compositions were determined according to the procedures described herein. 
The results are provided in Table 4 below. 
Example 28 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
In this Example the procedures used in Example 26 were substantially 
repeated with the exception that the gel compositions incorporated the 
Phenolic CB-B of Example 3. 
The Phenolic CB-B was dispersed in a beaker of acetone, vacuum filtered, 
and then rinsed repeatedly with deionized water until the pH of the wash 
water was close to neutral. The Phenolic CB-B was then dried at 
140.degree. C. for 12 hours. 
As in Example 24, the Phenolic CB-B was dispersed into the solution 
containing sodium silicate combined with sulfuric acid such that 10% of 
the total solids content was Phenolic CB-B and the balance was silica. In 
contrast to unmodified CB-B, addition of Phenolic CB-B was limited due to 
the stability of the surface groups. Only at pH values greater than 3 
could Phenolic CB-B be introduced into the sol such that the surface 
modification could be preserved. Therefore, the pH was carefully raised to 
3 with controlled addition of 1M NaOH and the appropriate amount of 
Phenolic CB-B dispersed into the sol. Gelation was achieved as before by 
controlled addition of 1M NaOH until the pH of the sol reached 5. 
After gelation, the materials were aged at 50.degree. C. for 1-2 hours as 
before, removed from the molds, and then washed free of salt for 12 hours 
at room temperature. The gel compositions were then aged up to 24 hours at 
70.degree. C. in deionized water. The gels were then solvent exchanged and 
dried from heptane as outlined in the prior Examples. 
The bulk density and rub-off of a representative sample of the gel 
compositions were determined according to the procedures described herein. 
The results are provided in Table 4 below. 
TABLE 4 
______________________________________ 
Sodium Silicate Precursor Gels (.ltoreq.50% Carbon) 
Ex- Carbon Drying Bulk Rub- 
ample Black Amount Solvent 
Density Off 
______________________________________ 
23 None None Heptane 
0.20 g/cm3 
-- 
24 CB-A 10% Heptane 
0.22 g/cm3 
25 
25 Modified CB-A 
10% Heptane 
0.21 g/cm3 
15 
26 CB-B 10% Heptane 
0.19 g/cm3 
16 
27 Modified CB-B 
10% Heptane 
0.19 g/cm3 
7 
28 Phenolic CB-B 
10% Heptane 
0.21 g/cm3 
2.5 
______________________________________ 
Alkoxide Precursor (Greater than 50%, by Weight (Solids) Loading) Examples 
Examples 29-34 are directed to gels produced from an alkoxide precursor and 
greater than 50%, by weight (solids), of a carbonaceous component. 
Example 29 
The steps from Example 11 were repeated with the exception that the amount 
of CB-A was increased to 60% of the total solids contents and the aging 
and drying steps were changed. As before, the appropriate amount of CB-A 
was added and the sol was diluted with ethyl alcohol to maintain a 
constant total solids content. Gelation was initiated in the same fashion 
as in previous examples 5-22. The gels were then aged for 24 hours at 
50.degree. C. in the sealed cylindrical molds. Instead of washing with 
water and aging at 70.degree. C., these gels were then dried directly from 
the mother liquor, first at 50.degree. C. for 10 hours, then at 
140.degree. C. for 10 hours. 
The resulting products were incoherent bodies largely comprising fines. The 
bulk density of a representative sample of the resulting product was 
determined by the procedure described herein. The result is set forth in 
Table 5 below. 
Example 30 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
In this Example the procedures used in Example 29 were substantially 
repeated with the exception that the gel compositions incorporated the 
Modified CB-A of Example 1. 
As in previous examples, the Modified CB-A was washed and then dispersed 
into the partially hydrolyzed silica solution such that 60% of the total 
solids content was Modified CB-A and the balance was silica. As before, 
the sol was diluted with ethyl alcohol to maintain a constant total solids 
content and gelation was initiated in an analogous fashion. The gels were 
then dried directly from the mother liquor as in Example 29, by aging for 
24 hours at 50.degree. C. in the sealed cylindrical molds, then at 
140.degree. C. for 10 hours. 
The resulting products were in the form of solid, one-piece pellets which 
were physically hard. There was a negligible amount of carbon fines and 
the gel article was very durable and coherent when compared to the gel 
article made with an unmodified carbonaceous material in Example 29. 
The bulk density of a representative sample of the resulting product was 
determined by the procedure described herein. The result is set forth in 
Table 5 below. 
Example 31 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
The steps from Example 30 were repeated with the exception that the amount 
of Modified CB-A was increased to 70% of the total solids, the balance 
being silica. As before, the sol was diluted with ethyl alcohol to 
maintain a constant total solids content and gelation was initiated in an 
analogous fashion. The gels were then aged for 24 hours at 50.degree. C. 
in the sealed cylindrical molds and then dried directly from the mother 
liquor, first at 50.degree. C. for 10 hours, then at 140.degree. C. for 10 
hours. 
The resulting pellets were hard and could be handled easily without 
breakage or generation of fines. The bulk density of a representative 
sample of the resulting product was determined by the procedure described 
herein. The result is set forth in Table 5 below. 
Example 32 
In this Example the procedures used in Example 29 were substantially 
repeated utilizing a different carbon black, designated herein as "CB-C", 
having the analytical properties set forth in Table 1. 
The CB-C was dispersed into the partially hydrolyzed silica solution such 
that 80% of the total solids content was CB-C and the balance was silica. 
As before, the sol was diluted with ethyl alcohol to maintain a constant 
total solids content and gelation was initiated in an analogous fashion. 
The gels were then aged for 24 hours at 50.degree. C. in the sealed 
cylindrical molds and then dried directly from the mother liquor, first at 
50.degree. C. for 10 hours, then at 140.degree. C. for 10 hours. 
The resulting article was analogous to that of Example 29, namely a weak, 
broken down gel was formed which consisted largely of carbon fines. The 
network was not coherent and lacked the structural integrity seen in the 
examples of the gel compositions of the present invention. 
The bulk density of a representative sample of the resulting product was 
determined by the procedure described herein. The result is set forth in 
Table 5 below. 
Example 33 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
In this Example the procedures used in Example 32 were substantially 
repeated with the exception that the gel compositions incorporated the 
Modified CB-C of Example 4. 
As in previous examples, the Modified CB-C was washed and then dispersed 
into the partially hydrolyzed silica solution such that 80% of the total 
solids content was Modified CB-C and the balance was silica. As before, 
the sol was diluted with ethyl alcohol to maintain a constant total solids 
content and gelation was initiated in an analogous fashion. The gels were 
then aged for 24 hours at 50.degree. C. in the sealed cylindrical molds 
and then dried directly from the mother liquor, first at 50.degree. C. for 
10 hours, then at 140.degree. C. for 10 hours. 
The resulting articles were pellets similar in appearance and integrity to 
those produced in Examples 30 and 31. Only a minimal amount of carbon 
fines existed and the gel was very coherent. 
The bulk density of a representative sample of the resulting product was 
determined by the procedure described herein. The result is set forth in 
Table 5 below. 
Example 34 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
The steps from Example 33 were repeated with the exception that the amount 
of Modified CB-C which was utilized in the gel composition was increased 
to 85% of the total solids content. As before, the appropriate amount of 
Modified CB-C was added, and the sol was diluted with ethyl alcohol to 
maintain a constant total solids content and gelation was initiated in an 
analogous fashion. The gels were then aged for 24 hours at 50.degree. C. 
in the sealed cylindrical molds and then dried directly from the mother 
liquor, first at 50.degree. C. for 10 hours, then at 140.degree. C. for 10 
hours. 
The resulting pellets could be handled easily without breakage or 
generation of fines. The bulk density of a representative sample of the 
resulting product was determined by the procedure described herein. The 
result is set forth in Table 5 below. 
Example 35 
This example illustrates the production of a gel composition of the present 
invention comprising a carbon black attached to a gel component. 
The steps from Example 33 were repeated with the exception that the amount 
of Modified CB-C which was utilized in the gel composition was increased 
to 90% of the total solids content As before, the appropriate amount of 
Modified CB-C was added and the sol was diluted with ethyl alcohol to 
maintain a constant total solids content and gelation was initiated in an 
analogous fashion. The gels were then aged for 24 hours at 50.degree. C. 
in the sealed cylindrical molds and then dried directly from the mother 
liquor, first at 50.degree. C. for 10 hours, then at 140.degree. C. for 10 
hours. 
The resulting pellets could be handled easily without breakage or 
generation of fines. The bulk density of a representative sample of the 
resulting product was determined by the procedure described herein. The 
result is set forth in Table 5 below. 
TABLE 5 
__________________________________________________________________________ 
Alkoxide Precursor Gels (&gt;50% Carbon) 
Carbon Drying Bulk 
Example 
Black Amount 
Solvent Density 
Form 
__________________________________________________________________________ 
29 CB-A 60% Mother liquor 
0.53 g/cm3 
Fines 
30 Modified CB-A 
60% Mother liquor 
0.54 g/cm3 
Pellet 
31 Modified CB-A 
70% Mother liquor 
0.61 g/cm3 
Pellet 
32 CB-C 80% Mother liquor 
0.66 g/cm3 
Fines 
33 Modified CB-C 
80% Mother liquor 
0.65 g/cm3 
Pellet 
34 Modified CB-C 
85% Mother liquor 
0.66 g/cm3 
Pellet 
35 Modified CB-C 
90% Mother liquor 
0.63 g/cm3 
Pellet 
__________________________________________________________________________ 
The results of Examples 29-35 illustrate that gel compositions of the 
present invention, Examples 30, 31 and 33-35, produced with a carbonaceous 
component attached to the gel component are coherent solids. In contrast, 
gel compositions produced with a carbonaceous component which was not 
attached to the gel component, Examples 29 and 32, fell apart. 
These results would indicate, to one of ordinary skill in the art, that gel 
compositions of the present invention, Examples 30, 31 and 33-35, are 
advantageous for use as adsorbents, in comparison to the gel compositions 
of Examples 29 and 32 which fell apart. 
SUMMARY OF RESULTS 
As a whole, the SEM and Rub-off data from the foregoing examples 
illustrates that in the gel compositions of the present invention the 
carbonaceous component (Modified CB-A, Modified CB-B, Phenolic CB-B and 
Modified CB-C) is attached to the gel component. 
In particular, the gel compositions of the present invention produced in 
Examples 12-17, 19-20, 22, 25 and 27-28, having the carbonaceous component 
attached to the gel component have lower Rub-Off than comparable gel 
compositions produced in Examples 6-11, 18, 21, 24 and 26 wherein the 
carbonaceous component is not attached to the gel component. Although the 
data is not presented above, similar results would be expected for gel 
compositions of the present invention produced in 30-31 and 33-35, having 
the carbonaceous component attached to the gel component, in comparison to 
the gel compositions produced in Examples 29 and 32 wherein the 
carbonaceous component is not attached to the gel component. 
Similarly, the SEM photographs, in particular FIG. 3 of the gel composition 
of the present invention of Example 14, FIG. 5 of the gel composition of 
the present invention of Example 19, FIG. 6 of the gel composition of the 
present invention of Example 20 and FIG. 8 of the gel composition of the 
present invention of Example 22, illustrate that the modified carbon 
blacks are attached to the silica gel component in the gel compositions of 
the present invention. As illustrated in FIGS. 3, 5, 6 and 8, minimal 
amounts, or none of, the attached carbonaceous component (modified carbon 
black) appears as a distinct aggregate in fracture surface SEM's of these 
gel compositions. These results indicate that the modified carbon black is 
attached to the silica gel component in several places and that the silica 
to carbon black link is stronger than the silica to silica links in 
conventional gel compositions which do not include a carbonaceous 
component attached to the gel component. 
In contrast, as illustrated in FIGS. 2, 4 and 7, fracture surface SEM's of 
gel compositions which include a carbonaceous component which is not 
attached to the gel component, show distinct aggregates of the carbon 
black. In these gel compositions, the carbon black is not attached to the 
silica gel component. 
It should be clearly understood that the forms of the present invention 
herein described are illustrative only and are not intended to limit the 
scope of the invention.