Elastomeric chlorinated polyethylene

ACS polymers, developed primarily in Japan, are grafts of acrylonitrile and styrene onto elastomeric chlorinated polyethylene. Although the polymer has good weathering properties it is somewhat susceptible to thermal degradation during processing and to date these polymers have been of limited interest. 

CPE is the standardized acronym for thermoplastic chlorinated polyethylene. CM is the standardized acronym for elastomeric chlorinated polyethylene. 

Thermoplastics. There are five elastomeric membranes that are thermoplastic. Two materials, chlorinated polyethylene (CPE) and polyisobutylene (PIB), are relatively obscure. Thermoplastic materials can be either heat-fused or solvent-welded. In contrast to Hypalon and uncured EPDM, this abiHty to fuse the membranes together remains throughout the life of the material. However, cleaning of the membrane surface after exposure to weather is required. Correct cleaning procedures for specific membranes are available from the individual manufacturer. 

Chlorinated polyethylene CPEs provide a very wide range of properties from soft/ elastomeric to hard. They have inherent oxygen and ozone resistance, have improved resistance (compared to PEs) to chemical extraction, resist plasticizers, volatility, and weathering. Products do not fog at high temperatures as do PVCs and can be made flame retardant. 

At room temperature, PE is a semi-crystalline plastomer (a plastic which on stretching shows elongation like an elastomer), but on heating crystallites melt and the polymer passes through an elastomeric phase. Similarly, by hindering the crystallisation of PE (that is, by incorporating new chain elements), amorphous curable rubbery materials like ethylene propylene copolymer (EPM), ethylene propylene diene terpolymer (EPDM), ethylene-vinyl acetate copolymer (EVA), chlorinated polyethylene (CM), and chlorosulphonated polyethylene (CSM) can be prepared. 

On the other hand, some mechanically compatible blends as well as some dispersed two-phase systems have made respectable inroads into the commercial scene. Many of these are blends of low-impact resins with high-impact elastomeric polymers examples are polystyrene/rubber, poly (styrene-co-acrylonitrile) /rubber, poly (methyl methacrylate) /rubber, poly (ethylene propylene)/propylene rubber, and bis-A polycarbonate/ ABS as well as blends of polyvinyl chloride with ABS or PMMA or chlorinated polyethylene. 

The moderate random chlorination of polyethylene suppresses crystallinity and yields chlorinated polyethylene elastomer (CPE), a rubber-like material that can be crosslinked with organic peroxides. The chlorine (Cl) content is in the range of 36 to 42%, compared to 56.8% for PVC. Such elastomer has good heat and oil resistance. It is also used as a plasticizer for PVC. They provide a very wide range of properties from soft/elastomeric too hard. They have inherent oxygen and ozone resistance, resist plasticizers, volatility, weathering, and compared to PEs have improved resistance to chemical extraction. Products do not fog at high temperatures as do PVCs and can be made flame retardant. 

Atactic poly(methyl methacrylate) Atactic polystyrene Butyl-rubber Chlorinated polyethylene Deuterated high density polyethylene Ethylene butylacrylate Elastomeric copolymer from ethylene and ethyl acrylate Elastomeric terpolymer from ethylene, propylene and a non-conjugated diene Elastomeric ethylene-propylene... 

Acrylonitrile-chlorinated polyethylene-styrene copolymer Elastomeric ethyl (or other) acrylate-ethylene copolymer Terpolymer from acrylonitrile, ethylene-propylene elastomer, and styrene... 

Impact Modifiers Impact modifiers are either systems with spherical elastomer particles in a rigid polymer matrix or they are systems with a honeycomb, network type of dispersed elastomeric phase. For the spherical elastomeric particles, examples are acrylonitrile butadiene styrene (ABS), methacrylate-butadiene-styrene (MBS) and acrylics. These systems are either graft copolymers of methyl methacrylate-butyl acrylate-styrene or methyl methacrylate-ethylhexyl acrylate-styrene. For the honeycomb, network type of dispersed elastomeric phase ethylene vinyl acetate (EVA) and chlorinated polyethylene (CPE) or directly dispersed rubber are examples. Both of these two impact modifiers exist in the polymeric form, hence they can hardly migrate and evaporate because of their size. As a result, they pose almost no problems to health. For PVC window frame production, usually the first type (and acrylic impact modifiers) are used while MBS modifiers are found to be very effective in plasticised as well as in rigid PVC. CPE is mainly used in PVC for products like sheet, pipe, gutters and sidings. 

Ta b I e 5.62 Upper and lower temperature limits for elastomeric materials (R C backbone with unsaturated units, M C backbone with only saturated units, 0 both C and 0 in the backbone, U C, N and 0 in the backbone, T C and S in the backbone, Q siloxane backbone NR natural rubber, IR isoprene rubber, BR butadiene rubber, CR chloroprene rubber, SBR styrene butadiene rubber, NBR nitrile rubber, HR butyl rubber, EPDM ethylene propylene ter-rubber, EAM ethylene vinyl acetate rubber, FKM fiuoro rubber, ACM acrylate rubber, CSM chlorosulfonated polyethylene, CM chlorinated polyethylene, ECO epichlorohydrin rubber (epichlorohydrin, ethylene oxide), AU polyurethane rubber (did), EU polyurethane rubber (diisocyanate), VMQ silicone rubber) specialties [229]... 

Chlorinated polyethylene (CPE) After a starting polyethylene has been chlorinated, the resulting material is typically 25-50 wt.% chlorine. The properties range from thermoplastic to elastomeric. Applications for CPE include automotive hoses, tubing, and wire jacketing plus extensive membranes for roofing. It ean be an impact modifier for PVC. 

Unlike most elastomeric polymers, which are made by direct polymerization of monomers or comonomers, chlorosulfonated polyethylene, as the name implies, is made by chemical modification of a preformed thermoplastic polymer. The chlorination and chlorosulfonation reactions are usually carried out simultaneously but may be carried out ia stages. 

Elastomeric polymers can be produced by the chlorination or chlorosulfonation of polyethylene. Both products start with polyethylene, either in solution or in aqueous suspension, which then is reacted to give the specified... 

In 2002 Dow Chemical announced their initial market offering of an elastomeric fiber based on monofilament polyethylene to be called Lastol. This is resistant to chlorine and is to be priced to compete directly with Spandex fiber derived from polyurethane technology [8]. 

Chlorosulfonated polyethylene (CSM) [68037-39-8] describes a group of curable, halogenated olefin polymers, first introduced to the rubber industry by E. I. du Pont de Nemours and Co. in 1951 (1-5) under the trade name of Hypalon. They contain pendant chlorine and sulfonyl chloride groups and vary in consistency from soft and elastomeric to hard and plastic. The chemical structure may be represented by... 

The optimum chlorine content for an amorphous elastomer is the minimum amoimt required to destroy the crystalline segments. This optimum level depends on the number and types of crystallites in the polyethylene precursor, the randomness of chlorine distribution along the chain, and chain-to-chain distribution. So, for HDPE, the optimum chlorine level for elastomeric properties is at about 35%... 

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