Chlorinated polyfvinyl chloride

Whilst such stabilisers have found use in many chlorine-containing polymers their main application has been with polyfvinyl chloride). These additives will be considered in Chapter 12. 

Approximately 10 million tons of 1,2-dichloroethane are manufactured each year in the United States by the reaction of ethylene with chlorine. The process is the first step in making PVC [polyfvinyl chloride)] plastics. 

Investigation of the kinetics of the reaction of 4-chloro-2-pentene, an allylic chloride model for the unstable moiety of polyfvinyl chloride), with several thermal stabilizers for the polymer has led to a better understanding of the stabilization mechanism. One general feature of the mechanism is complexing of the labile chlorine atom by the metal atom of the stabilizer. A second general feature is substitution of the complexed chlorine atom by a ligand (either carboxylate or mercaptide) bound to the metal. Stabilization requires that the new allylic substituent (ester or sulfide) be more thermally stable than the allylic chlorine. The isolation of products from stabilizer-model compound reactions supports the substitution hypothesis of poly(vinyl chloride) stabilization. 

Rigid polyfvinyl chloride) (PVC) compounds and chlorinated poly(vinyl chloride) (CPVC) compounds... 

Polymeric carbocations have been formed from a chlorine-containing polymer such as chlorinated SBR and polystyrene, polyfvinyl chloride), and polychloroprene, by reaction with (C2H5)2A1C1, for example... 

CPVC Chlorinated polyfvinyl chloride) HRC Rockwell C hardness number... 

Because titanium ignites spontaneously in dry chlorine, it must be avoided. Graphite, glass, and glazed porcelain are used where there is a risk of moisture in the dry chlorine gas, and polyfvinyl chloride) (PVC) or chlorinated PVC and polyester resins are suitable if the temperature limits of these materials are regarded. 

Bromine and chlorine add rapidly to alkenes to yield 1,2-dihalides, a process called halogenation. For example, more than 18 million tons 1,2-dichloroethane (ethylene dichloride) is synthesized worldwide each year, much of it by addition of GI2 to ethylene. The product is used both as a solvent and as starting material for the manufacture of polyfvinyl chloride), PVG. Fluorine is too reactive and difficult to control for most laboratory applications, and iodine does not react with most alkenes. 

Fig. 11. Effect of temperature on electric strength of polymers. A, Polyfvinyl alcohol) B, polyfmethyl methacrylate) C, polyfvinyl chloride-co-vinyl-acetate) D, chlorinated polyethylene E, mica F, polystyrene G, polyethylene and H, polyisobutylene (31).

An example is the spectrum of the carbon-chlorine region of the highly syndio-tactic polyfvinyl chloride) made by the urea-clathrate route [95]. It has two peaks and a high-frequency shoulder. The second derivative spectrum shows two negative peaks at the positions of the two peaks in the original spectrum. There also appears to be a peak at 638 cm in the second derivative spectrum this peak is assigned to long planar syndiotactic sequences. The second derivative spectrum of a commercial polyfvinyl chloride) reveals six peaks. 

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