Carboxylated styrene-butadiene copolymers

One method (116) of producing cellular polymers from a variety of latexes uses primarily latexes of carboxylated styrene—butadiene copolymers, although other elastomers such as acryUc elastomers, nitrile mbber, and vinyl polymers can be employed. 

Chem. Descrip. Carboxylated styrene-butadiene copolymer latex Uses Associative thickener for adhesives, suitable for coated and uncoated paper. Mylar, cellulose acetate, metalized polyester, aluminum, nonskid coating, and mastic substrates Features Very efficient... 

Synonyms Carboxylated styrene-butadiene copolymer Uses Nonwoven binder for textiles In Interior vapor barrier primer sealers and flat wall paint binder for paper coatings food-pkg. adhesives/ paper... 

Carboxylated styrene-butadiene copolymer. See Carboxylated styrene butadiene... 

Waterborne dispersed polymers include both synthetic polymer dispersions and natural rubber. Synthetic polymer dispersions are produced by emulsion polymerization. A substantial part of the synthetic polymer dispersions is commercialized as dry products these include SBR for tires, nitrile rubbers, about 10% of the total PVC production, 75% of the total ABS and redispersable powders for construction materials. Carboxylated styrene-butadiene copolymers, acrylic and styrene-acrylic latexes and vinyl acetate homopolymer and copolymers are the main polymer classes commercialized as dispersions. The main markets for these dispersions are paints and coatings, paper coating, adhesives and carpet backing. 

Emulsion polymerization is the leading technique to produce colloidal polymer dispersions. Carboxylated styrene-butadiene copolymers, acrylic and styrene-acrylic latexes, and vinyl acetate homopolymer and copolymers are the main polymer classes produced by this technique. These products are commercialized as dispersions and as dry products. 

The latex stability characteristics related to surface chemistry were analyzed by Polatajko-Lobos and Xanthopoulo [47] by studying the relationships between the concentration of surface-bound functional groups on carboxylated styrene-butadiene copolymer latex particles and the mechanical and chemical stability of the latexes synthesized. 

Zhao, J. and Brown, W. 1995. Adsorption of a nonionic surfactant (C12E7) on carboxylated styrene-butadiene copolymer latex particles. J. Colloid Interface Sci. 169 39-Al. 

Acrylics. Acetone is converted via the intermediate acetone cyanohydrin to the monomer methyl methacrylate (MMA) [80-62-6]. The MMA is polymerized to poly(methyl methacrylate) (PMMA) to make the familiar clear acryUc sheet. PMMA is also used in mol ding and extmsion powders. Hydrolysis of acetone cyanohydrin gives methacrylic acid (MAA), a monomer which goes direcdy into acryUc latexes, carboxylated styrene—butadiene polymers, or ethylene—MAA ionomers. As part of the methacrylic stmcture, acetone is found in the following major end use products acryUc sheet mol ding resins, impact modifiers and processing aids, acryUc film, ABS and polyester resin modifiers, surface coatings, acryUc lacquers, emulsion polymers, petroleum chemicals, and various copolymers (see METHACRYLIC ACID AND DERIVATIVES METHACRYLIC POLYMERS). 

Many synthetic latices exist (7,8) (see Elastomers, synthetic). They contain butadiene and styrene copolymers (elastomeric), styrene—butadiene copolymers (resinous), butadiene and acrylonitrile copolymers, butadiene with styrene and acrylonitrile, chloroprene copolymers, methacrylate and acrylate ester copolymers, vinyl acetate copolymers, vinyl and vinyUdene chloride copolymers, ethylene copolymers, fluorinated copolymers, acrylamide copolymers, styrene—acrolein copolymers, and pyrrole and pyrrole copolymers. Many of these latices also have carboxylated versions. 

Almost all synthetic binders are prepared by an emulsion polymerization process and are suppHed as latexes which consist of 48—52 wt % polymer dispersed in water (101). The largest-volume binder is styrene—butadiene copolymer [9003-55-8] (SBR) latex. Most SBRlatexes are carboxylated, ie, they contain copolymerized acidic monomers. Other latex binders are based on poly(vinyl acetate) [9003-20-7] and on polymers of acrylate esters. Poly(vinyl alcohol) is a water-soluble, synthetic biader which is prepared by the hydrolysis of poly(viayl acetate) (see Latex technology Vinyl polymers). 

Polymeric particles can be constructed from a number of different monomers or copolymer combinations. Some of the more common ones include polystyrene (traditional latex particles), poly(styrene/divinylbenzene) copolymers, poly(styrene/acrylate) copolymers, polymethylmethacrylate (PMMA), poly(hydroxyethyl methacrylate) (pHEMA), poly(vinyltoluene), poly(styrene/butadiene) copolymers, and poly(styrene/vinyltoluene) copolymers. In addition, by mixing into the polymerization reaction combinations of functional monomers, one can create reactive or functional groups on the particle surface for subsequent coupling to affinity ligands. One example of this is a poly(styrene/acrylate) copolymer particle, which creates carboxylate groups within the polymer structure, the number of which is dependent on the ratio of monomers used in the polymerization process. 

In a three-necked flask equipped with stirrer, reflux condenser, and N2 inlet, 200 grams of a 1% solution of carboxylated styrene-butadiene block copolymer in o-dichlorobenzene and 2 grams TiOo were stirred at various temperatures for 3 hours. (Typical temperatures in this treatment were 110°, 150°, and 178°C.) After the heat treatment the Ti02 was isolated from the block copolymer solution by centrifuging for 1-2 hours at 2,000-2,200 rpm. After decanting the supernatant solution, the solid particles were washed with solvent and dried in vacuo for about 16 hours at 50°C. 

Following the guidelines established by Schechter s work, we dispersed titanium dioxide particles in 1% solutions of carboxylated styrene-butadiene block copolymers and stirred the dispersions at elevated temperatures in a nitrogen atmosphere. Typical data are shown in Table I. The dispersions (primary dispersions) in o-dichlorobenzene were quite stable. The titanium dioxide particles were isolated from these primary dispersions by centrifugation and were washed with toluene and finally with methanol. After drying in vacuo, samples of the block copolymer-titanium dioxide composites were submitted for carbon analysis. The... 

This work has demonstrated that carboxylated styrene-butadiene block copolymers are excellent dispersants for titanium dioxide particles in toluene. Combining our results with carboxylated block copolymers and homopolymers and Schechters (18) results with fatty acids, we can... 

The effects of improved wettability, entropic repulsion, and sterical hindrance undoubtedly play a role in stabilizing dispersed solid particles by block or graft copolymers. However, since the dispersions of titanium dioxide in toluene stabilized by carboxylated styrene-butadiene block copolymers are so much more stable than dispersions stabilized by carboxylated homopolymers under otherwise identical conditions, we must assume that an additional factor comes into play when block copolymers are used. The model in Figure 1 is an attempt to explain this additional... 

Polymer characterization is an important use of NIR spectrometry. Polymers can be made either from a single monomer, as is polyethylene, or from mixtures of monomers, as are styrene-butadiene rubber from styrene and butadiene and nylon 6-6, made from hexamethylenediamine and adipic acid. An important parameter of such copolymers is the relative amount of each present. This can be determined by NIR for polymers with the appropriate functional groups. Styrene content in a styrene-butadiene copolymer can be measured using the aromatic and aliphatic C—H bands. Nylon can be characterized by the NH band from the amine monomer and the C=0 band from the carboxylic acid monomer. Nitrogen-containing polymers such as nylons, polyurethanes, and urea formaldehyde resins can be measured by using the NH bands. Block copolymers, which are typically made of a soft block of polyester and a hard block containing aromatics, for example, polystyrene, have been analyzed by NIR. These analyses have utilized the... 

Styrene-1,3-butadiene copolymers with higher styrene contents (50-70%) are used in latex paints. Styrene and 1,3-butadiene terpolymerized with small amounts of an unsaturated carboxylic acid are used to produce latexes that can be crosslinked through the carboxyl groups. These carboxylated SBR products are used as backing material for carpets. Styrene copolymerized with divinyl benzene yields crosslinked products, which find use in size-exclusion chromatography and as ion-exchange resins (Sec. 9-6). 

The two extremes on the styrene-butadiene block copolymer composition scale are homopolymers of butadiene or styrene, respectively. To test the usefulness of homopolymers as dispersants, polybutadiene (PB) was carboxylated by adding thioglycolic acid, and polystyrene (PS) having carboxylic groups was prepared by copolymerizing small amounts of acrylic acid (AA) into the styrene chain. Adsorption experiments with these carboxylated homopolymers are listed in Table V. In the first... 

For the styrene-butadiene-methacrylic acid copolymers, meth-acrylic acid was also found in the serum, on the particle surface, and buried inside the particles. At 23% degree of neutralization, less methacrylic acid was found in the serum and on the particle surface than with acrylic acid, i.e., more was buried inside the particle. At 3.0% methacrylic acid, the amount incorporated into the particle was fairly constant, independent of the degree of neutralization. The different distributions of methacrylic and acrylic acids were explained by their different distributions between the monomer-polymer and aqueous phases. Thus these characterization results show the effect of vinyl carboxylic acid type and concentration on the loci of the carboxyl groups. Similar correlations could be made with other systems. 

Effect of Molecular Structure. Table III shows the effects of the molecular structure of the liquid polymer on the fracture energy of toughened systems. The CTIN is a carboxyl terminated isoprene-acrylonitrile copolymer CTBS is a carboxyl terminated butadiene and styrene copolymer, and CTA is a copolymer of ethyl acrylate-butyl acrylate. 

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