Styrene-butadiene-vinylpyridine polymer

It is claimed that styrene/butadiene diblock polymers bring about an improvement in the hardness, strength, and processability of polybutadiene elastomers (27), as well as an improvement in the ozone resistance of neoprene rubber (28). Styrene diblock polymers have also been made with isoprene, a-methyIstyrene, methyl methacrylate, vinylpyridine, and a-olefins. Block copolymers of ethylene, propylene, and other a-olefins with each other have been made as well. Heteroatom block copolymers based on styrene or other hydrocarbons and alkylene oxides, phenylene oxides, lactones, amides, imides, sulfides, or slloxanes have been prepared. 

Tire Cord. Melamine resins are also used to improve the adhesion of mbber to reinforcing cord in tires. Textile cord is normally coated with a latex dip solution composed of a vinylpyridine—styrene—butadiene latex mbber containing resorcinol—formaldehyde resin.. The dip coat is cured prior to use. The dip coat improves the adhesion of the textile cord to mbber. Further improvement in adhesion is provided by adding resorcinol and hexa(methoxymethyl) melamine [3089-11 -0] (HMMM) to the mbber compound which is in contact with the textile cord. The HMMM resin and resorcinol cross-link during mbber vulcanization and cure to form an interpenetrating polymer within the mbber matrix which strengthens or reinforces the mbber and increases adhesion to the textile cord. Brass-coated steel cord is also widely used in tires for reinforcement. Steel belts and bead wire are common apphcations. Again, HMMM resins and resorcinol [108-46-3] are used in the mbber compound which is in contact with the steel cord to reinforce the mbber and increase the adhesion of the mbber to the steel cord. This use of melamine resins is described in the patent Hterature (49). 

Synthetic. The main types of elastomeric polymers commercially available in latex form from emulsion polymerization are butadiene—styrene, butadiene—acrylonitrile, and chloroprene (neoprene). There are also a number of specialty latices that contain polymers that are basically variations of the above polymers, eg, those to which a third monomer has been added to provide a polymer that performs a specific function. The most important of these are products that contain either a basic, eg, vinylpyridine, or an acidic monomer, eg, methacrylic acid. These latices are specifically designed for tire cord solutioning, papercoating, and carpet back-sizing. 

L. Liang and S. Ying, Charge-mosaic membrane from gamma-irradiated poly(styrene-butadiene-4-vinylpyridine) triblock copolymer, J. Polym. Sci., Polym. Phys., 1993, 31, 1075-1081. 

Soum and Fontanille report that di-s-butyl magnesium generates living polymer from 2-vinylpyridine without the involvement of the side-reactions that afflict the polymerization initiated by alkali metal alkyls the resulting polymer has an isotacticity index of 0.9. Arai et al. have synthesized styrene-butadiene-4-vinylpyridine triblock copolymers. Hogen-Esch et a/. have continued their study of the stereochemistry of the anionic polymerization of 2-vinylpyridine in THF solution. Oligomers were synthesized by addition of alkali salts of 2-ethylpyridine to 2-vinylpyridine termination was effected by reaction with methyl iodide. Highly isotactic products were obtained with U and Na as counterions but with K or Rb there was no stereoselection. Epimerization resulted in the expected statistical mixtures of stereoisomers and it was concluded that stereoselection is kinetically controlled. 

AlkyUithium compounds are primarily used as initiators for polymerizations of styrenes and dienes (52). These initiators are too reactive for alkyl methacrylates and vinylpyridines. / -ButyUithium [109-72-8] is used commercially to initiate anionic homopolymerization and copolymerization of butadiene, isoprene, and styrene with linear and branched stmctures. Because of the high degree of association (hexameric), -butyIUthium-initiated polymerizations are often effected at elevated temperatures (>50° C) to increase the rate of initiation relative to propagation and thus to obtain polymers with narrower molecular weight distributions (53). Hydrocarbon solutions of this initiator are quite stable at room temperature for extended periods of time the rate of decomposition per month is 0.06% at 20°C (39). 

These include the vinyl addition polymers derived from common monomers like methyl methacrylate [9], acrylonitrile [10-12], styrene [13],butadiene [14], 4-vinylpyridine [15],acrylamide [15],andtetrafluoro ethylene [16]. In addition, selective polymers like polyfvinyl alcohol) [17],poly(N-vinyl pyrrolidone) [18], polyfethylene glycol) (PEG) [19], and others [20] have also been used. 

Figure 2 Example polymers that can undergo phase separation, (a) Poly(ethylene oxide)-f)-poly(butylene oxide), (PEO-f)-PBO) (b) poly(ethyleneoxide)-fc-poly(styrene), (PEO-i>-PS) (c) poly(styreneFi -poly(4-vinylpyridine), (PS-i>-P4VP) (d) poly(ethylene oxide)-f)-poly(caprolactone), (PEO-fc-PCL) (e) poly(ethylene oxide)-f)-poly(butadiene), (PEO-f)-PB) and (f) polyfacrylic acid)-fc-poly(styrene), (PAA-1>-PS).

This assembly chemistry is only limited by the preparation of an appropriate amphiphilic or hydrophobic diblock copolymer. With the structure and chemical composition of the resultant nanoparticles readily tunable using a wide range of block copolymers that are synthetically available. A broad range of polymers have been utilized as the core hydrophobic domain of shell-crosslinked nanoparticles and include styrene, isoprene, butadiene, caprolactone, poly (ethylene oxide), acrylates, methacrylate and acrylamides. Monomers that have been used to prepare the hydrophilic water-soluble domain include, among others, poly(ethylene glycol), acrylic acid, 4-vinylpyridine, (meth)acrylic acid, 2-dimethylaminoethyl methacrylate and Wisopropylacrylamide. 

Figwe 13 Influence of the block sequence in triblock terpolymers of styrene (S), butadiene (B), and 2-vinylpyridine (V). Reprinted with permission from Abetz, V. In Encyclopedia of Polymer Science and Technology, 3rd ed. Kroschwitz, J. I., Ed. John Wiley Sons, Inc. New York 2002 Vol. 1, pp 482-523." ... 

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