Chloride homopolymers, copolymers

Solubility Characteristics of Today s Vinyl Chloride Homopolymers, Copolymers, and Terpolymers... 

Vinyhdene chloride copolymers are available as resins for extmsion, latices for coating, and resins for solvent coating. Comonomer levels range from 5 to 20 wt %. Common comonomers are vinyl chloride, acrylonitrile, and alkyl acrylates. The permeability of the polymer is a function of type and amount of comonomer. As the comonomer fraction of these semicrystalline copolymers is increased, the melting temperature decreases and the permeability increases. The permeability of vinylidene chloride homopolymer has not been measured. 

Random copolymers of vinyl chloride and other monomers are important commercially. Most of these materials are produced by suspension or emulsion polymerization using free-radical initiators. Important producers for vinyl chloride—vinyUdene chloride copolymers include Borden, Inc. and Dow. These copolymers are used in specialized coatings appHcations because of their enhanced solubiUty and as extender resins in plastisols where rapid fusion is required (72). Another important class of materials are the vinyl chloride—vinyl acetate copolymers. Principal producers include Borden Chemicals Plastics, B. F. Goodrich Chemical, and Union Carbide. The copolymerization of vinyl chloride with vinyl acetate yields a material with improved processabihty compared with vinyl chloride homopolymer. However, the physical and chemical properties of the copolymers are different from those of the homopolymer PVC. Generally, as the vinyl acetate content increases, the resin solubiUty in ketone and ester solvents and its susceptibiUty to chemical attack increase, the resin viscosity and heat distortion temperature decrease, and the tensile strength and flexibiUty increase slightly. 

This chapter has so far dealt with the major fields of use of vinyl chloride polymers, namely plasticised PVC homopolymer, unplasticised PVC, including impact-modified grades, and copolymers particular based on vinyl acetate. There are, however, five particular special forms of vinyl chloride polymer which merit separate consideration, namely crystalline PVC, after-chlorinated PVC (often known as CPVC) and certain graft copolymers and two vinyl-chloride-based copolymers. 

Copolymers of vinyl chloride with 2-10% propylene became available in the USA in 1973 (Sta-Flow by Air Products and Chemicals Inc.). Compared with the vinyl chloride homopolymer these copolymers have a reduced tendency to dehydrochlorination and thus improved heat stability. This is of importance both in application and during processing, and one particular claim made for these products is their ease of moulding. 

ISO 182, Parts 1-4, Plastics - Determination of the tendency of compounds and products based on vinyl chloride homopolymers and copolymers to evolve hydrogen chloride and any other acidic products at elevated temperatures, 1990-1993. 

The mechanical admixture of low molecular weight monomers into polymers normally in the glassy state at room temperature in order to increase the flexibility and softness of the polymer has great technical importance. Thus, such plasticizers as di-2 ethyl n-hexyl phthalate are frequently incorporated into polyvinyl chloride, homopolymer or copolymer, to increase the flexibility and commercial value of this resin. Cast (1953) as well as Hellwege, Knappe and Semjonow (1959) have... 

The polymerization reaction in aqueous suspension of vinyl chloride in the presence of an ethylene-propylene saturated elastomer occurs with the formation of poly (vinyl chloride) homopolymer and rubber-poly (vinyl chloride) grafted copolymers. The first grafting reaction proceeds as far as diffusion of the monomer inside the particles in suspension is possible afterwards, some chain branching of grafted PVC is possible. Under our experimental conditions the amount of grafted rubber does not exceed 60% of the initial rubber and is little influenced by the type of initiator used. 

Mechanical Stability of Vinyl Chloride Homopolymer and Copolymer Latices... 

The object of this study was to clarify some aspects of the mechanism of shear-induced flocculation in colloidal dispersions. Vinyl chloride homopolymer and copolymer latices were prepared by emulsion polymerization using sodium dodecyl sulphate as emulsifier. Agglomeration behavior in these latices was studied by measuring the mechanical stability using a high speed stirring test. The latex particle size was measured by an analytical centrifuge. Molecular areas of emulsifier in the saturated adsorption layer at the surface of homopolymer and copolymer latex particles were estimated from adsorption titration data. 

The vinyl acetate content of such materials ranges between 3 and 40%, and the copolymers are more soluble and pliable than poly(vinyl chloride) homopolymer. They can be shaped mechanically at lower temperatures than homopolymers with the same degree of polymerization and are used mainly in surface coatings and products where exceptional flow and reproduction of details of a mold surface are needed. 

Evolved gas analysis, particularly in the form of TGA-DTA-MS, has obvious synthetic polymer applications. It has been applied to study the thermal behavior of homopolymers, copolymers, polymeric blends, composites, residual polymers, solvents, additives, and toxic degradation polymers. In the latter context, hydrogen chloride evolution from heated polyvinylchloride materials is readily quantified by TGA-DTA-MS and such data are of major significance in... 

Propenamide-2-propenoic acid polymer. See Acrylic acid/acrylamide copolymer 2-Propenamide, N-[[4-[(4,7,7-trimethyl-3-oxobicyclo [2.2.1] hept-2-ylidene) methyl] phenyl] methyl]-, homopolymer. See Polyacrylamidomethyl benzylidene camphor Propenamidopropyltrimethylammonium chloride, polymer with propenoic acid, butenoic acid, and/or alkyl propenoates. See Acrylamidopropyltrimonium chloride/acrylates copolymer... 

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