Thermoplasticity graft copolymers

R. Milkovich, M. T. Chiang, Chemically Joined Phase Separated Thermoplastic Graft Copolymers, U.S. Patent 3,786,116 (1974). 

Thermoplastic graft copolymers can be considered as branched block copolymers with many branch points. A graft copolymer of isobutylene on poly (ethylene) and a graft copolymer of styrene/acrylonitrile on acrylic rubber is used in industry. 

Moreover, commercially available triblock copolymers designed to be thermoplastic elastomers, not compatihilizers, are often used in Heu of the more appealing diblock materials. Since the mid-1980s, the generation of block or graft copolymers in situ during blend preparation (158,168—176), called reactive compatibilization, has emerged as an alternative approach and has received considerable commercial attention. 

Isocyanates can be added to solvent-borne CR adhesive solutions as a two-part adhesive system. This two-part adhesive system is less effective with rubber substrates containing high styrene resin and for butadiene-styrene block (thermoplastic rubber) copolymers. To improve the specific adhesion to those materials, addition of a poly-alpha-methylstyrene resin to solvent-borne CR adhesives is quite effective [76]. An alternative technique is to graft a methacrylate monomer into the polychloroprene [2]. 

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. 

Thermoplastic elastomers (TPE), 9 565-566, 24 695-720 applications for, 24 709-717 based on block copolymers, 24 697t based on graft copolymers, ionomers, and structures with core-shell morphologies, 24 699 based on hard polymer/elastomer combinations, 24 699t based on silicone rubber blends, 24 700 commercial production of, 24 705-708 economic aspects of, 24 708-709 elastomer phase in, 24 703 glass-transition and crystal melting temperatures of, 24 702t hard phase in, 24 703-704 health and safety factors related to, 24 717-718... 

Example 5-23) and of ABS-polymers (made from acrylonitrile, butadiene, and styrene), whereby grafting occurs in situ at the beginning of the polymerization process. The formed graft copolymers act in two ways As emulsifiers during the polymerization process and, secondly, in the solid end product as compatibilizer between the thermoplastic hard phase and the rubber-elastic dipersed phase (already in concentrations below 3%). 

Segro, N. R and W. Hodes, American Cyanamid Company Thermoplastic composition comprising a styrene polymer and a graft copolymer. U. S. 3,044,972 (July 17, 1962). 

Use of Crosslinked VC/PE Graft Copolymers for Cable Insulation. At high temperatures, plasticized PVC cable insulations show a rather high flow. This should be improved by crosslinking of the thermoplastic insulation material. Unfortunately, PVC is not easily cross-linkable by chemical agents. The presence of about 503 of grafted or... 

Thermoplastic Olefin. These thermoplastic elastomers are primarily blends, or block or graft copolymers, of ethylene/propylene rubber with polypropylene. 

The thermoplasticity of the graft copolymers can be verified by measurements of the glass transition temperature of the new solids. The glass transition temperature is the temperature at which an amorphous solid becomes ductile and is a characteristic of thermoplastic materials. Samples of 5-10 mg of reaction product were heated at 10°C/min in a differential scanning calorimeter to monitor heat capacity as a function of temperature. The temperature of each transition produced by each copolymer is shown in Table 8. 

Summary Graft copolymers with poly(organosiloxane) backbone and thermoplastic side chains have been synthesized via the "grafting fi om" method based on azo- and triazene modified poly(organosiloxane)s. Initiation of free radical polymerization is possible from the polymeric azo and triazene initiators after thermal decomposition of the labile frmctions in solution. The graft products have been characterized by NMR, GPC, and DSC. Stable, free standing films can be cast from the graft copolymers. 

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