Use of graft copolymers

Humphries M, Nemcek J, Cantwell JB et al. (1987) The use of graft-copolymers to inhibit the adhesion of bacteria to solid-surfaces. FEMS Microbiol Ecol 45 297-304... 

In addition to graft copolymer attached to the mbber particle surface, the formation of styrene—acrylonitrile copolymer occluded within the mbber particle may occur. The mechanism and extent of occluded polymer formation depends on the manufacturing process. The factors affecting occlusion formation in bulk (77) and emulsion processes (78) have been described. The use of block copolymers of styrene and butadiene in bulk systems can control particle size and give rise to unusual particle morphologies (eg, coil, rod, capsule, cellular) (77). 

Compatibilization along with dynamic vulcanization techniques have been used in thermoplastic elastomer blends of poly(butylene terephthalate) and ethylene propylene diene rubber by Moffett and Dekkers [28]. In situ formation of graft copolymer can be obtained by the use of suitably functionalized rubbers. By the usage of conventional vulcanizing agents for EPDM, the dynamic vulcanization of the blend can be achieved. The optimum effect of compatibilization along with dynamic vulcanization can be obtained only when the compatibilization is done before the rubber phase is dispersed. 

Using 4,4,-bis(4-hydroxyphenyl)pentanoic acid (BHPA)196 197 as comonomer, some polysulfones with pendent carboxylic groups were successfully synthesized.198199 Table 6.1 shows the structure of BHPA. The functional groups can be used for the preparation of graft copolymers. 

This area of research is receiving increasing attention due to a better understanding (and recognition) of the properties and potential applications of siloxane containing copolymers. A detailed discussion of this type of graft copolymers and their uses will be given in later sections. 

Anionic polymerization techniques can also be applied to the synthesis of graft copolymers 6 7 87 1U). Kennedy s classification 134) is used here as shown in Scheme 5. 

The enzymatic polymerization of lactones could be initiated at the hydroxy group of the polymer, which expanded to enzymatic synthesis of graft copolymers. The polymerization of c-CL using thermophilic lipase as catalyst in the presence of hydroxyethyl cellulose (HEC) film produced HEC-gra/f-poly( -CL) with degree of substitution from 0.10 to 0.32 [102]. 

Since isolation and drying of graft copolymers prior to se xsnification would not be a viable oomnercial procedure, future sc xmfications were carred out as before in the stirred sigma reactor with unisolated graft copolymer. However, the amount and concentration of sodium hydroxide used were the same as for Table IV. 

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