POLYVINYL HALIDE

Polyvinyl Halides. Chlorinated Polyvinyl Chloride It was produced in Germany up to three decades ago, but this was primarily a 1,1-disubstituted product of increased solubility for dry-spinning of fibers. Goodrich has developed a light-activated suspension chlorination process which produces 1,2-dichlorinated structures of increased hot strength, thermal stability, and flame resistance. 

The first truly synthetic resin was developed by Baekeland in 1911 (phenol-formaldehyde). This was soon followed by a petroleum-derived product called coumarone-indene, which did indeed have the properties of a resin. The first synthetic elastomer was polychloroprene (1931) originated by Nieuwland and later called neoprene. Since then many new types of synthetic polymers have been synthesized, perhaps the most sophisticated of which are nylon and its congeners (polyamides, by Carothers), and the inorganic silicone group (Kipping). Other important types are alkyds, acrylics, aminoplasts, polyvinyl halides, polyester, epoxies, and polyolefins. 

Polypropylene resins Polyetyrene resins Polyurethane resins Polyvinyl chloride resins Polyvinyl halide resins... 

Polyvinyl halide n. A term sometimes used (almost exclusively in patents) for polymers and co-polymers of vinyl chloride. Aside from polyvinyl fluoride, which is more similar structurally to polyethylene, and brominated butyl rubber, which has enjoyed some use in the automobile-tire industry, no polymers containing the other halogens (bromine, iodine, and astatine) exist in commerce. 

Polymers have been grouped into the following 10 categories aliphatic polyolefins, polystyrenes, polyvinyl halides, polyvinyl esters, cellulose esters, polyvinyl ethers, poly-ethers, aromatic polymers, copolymers and miscellaneous polymers. The molar cohesive energies (Eg) were calculated from their respective group increments according to the following equation ... 

Uses Solvent for nitrocellulose, ethyl cellulose, polyvinyl butyral, rosin, shellac, manila resin, dyes fuel for utility plants home heating oil extender preparation of methyl esters, formaldehyde, methacrylates, methylamines, dimethyl terephthalate, polyformaldehydes methyl halides, ethylene glycol in gasoline and diesel oil antifreezes octane booster in gasoline source of hydrocarbon for fuel cells extractant for animal and vegetable oils denaturant for ethanol in formaldehyde solutions to inhibit polymerization softening agent for certain plastics dehydrator for natural gas intermediate in production of methyl terLbutyl ether. 

Other radiolysis studies on chlorine and bromine compounds have included ethyl chloride , 1,3-dichloropropane , allyl halides , trichloroethylene and hexachlorobutadiene , hexachlorocyclopentadiene and other unsaturated chlorinated hydrocarbons - , hexachlorocyclohexane , chloro- and bromo-benzenes - - , phenyl ethyl bromides , polyvinyl chloride - - and... 

Amorphous Ti02/MV systems behave quite differently upon photo-excitation. MV2+ is not adsorbed on amorphous Ti02 and so instantaneous formation of MV+ is not observed. However, in the presence of electron donors such as polyvinyl alcohol (PVA), or halide ions, a slow growth of MV+ formation is observed over a period of several us (Fig. 10). In the case of PVA, a permanent reduction of MV2+ is observed as reported by GrStzel et al. (16), but in the case of Cl no permanent reduction is observed. Pulse photolysis studies show large yields of initially formed MV+, but rapid back reaction of MV+ and Cl2 yield the starting materials. In 0.1 M HClO the reduction of MV2+ is not efficient, as electron transfer from ClO - to the Ti02 hole is not efficient. 

Polyvinyl compounds are produced either by the polymerization of vinyl compounds CH2=CHX or by polymer analog reactions on polyvinyl compounds. The derivatives of poly(vinyl alcohol) -%CH2—CH(OHH- , poly(vinyl halides) -f-CH2—CHHal and poly-(vinyl amines) -%CH2—CH(NRiR2)- are of particular commercial importance. In contrast to these, poly(vinyl sulfides) -f-CH2—CH(SR)- are only of academic interest. Vinyl alcohol is unstable, since it transforms into acetaldehyde on formation. Therefore, poly(vinyl alcohol) is produced from poly(vinyl acetate). 

Polyvinyl fluoride. Polyvinyl fluoride (PVF) is a crystalline polymer available in film form and used as a lamination on plywood and other panels. The film is impermeable to many gases. PVF is structurally similar to polyvinyl chloride (PVC) except for the replacement of a chlorine atom with a fluorine atom. PVF exhibits low moisture absorption, good weatherability, and good thermal stability. Similar to PVC, PVF may give off hydrogen halides in the form of HF at elevated temperatures. However, PVF has a greater tendency to crystallize and better heat resistance than PVC. ... 

Scheme 7.24 Vinylation of aryl halides with commercially available di- and polyvinyl-siloxanes.

Other uses in photography involve silica-hardened gelatin surfaces on X-ray film (726), colloidal silica-modified silver halide emulsions for higher sensitivity (727), and silica-polyvinyl alcohol as a replacement for gelatin in image-receiving layers (728). 

The organotin halide chosen for most of this study was dibutyltin dichloride because of its low cost relative to other organotin halides and the observation from previous studies that other polymers, namely cellulose, and polyvinyl alcohol, which were modified through condensation with dibutyltin dichloride, showed good activity against a number of fungi tested. ... 

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