Vinyl ethers redox polymerization

Polymerization is carried out expeditiously in aqueous media using either redox or thermally generated free-radical systems anhydrous techniques may be also used. In general, there appears to be no gross difference in reactivity rates with different substituents on the vinyl ethers. However, where slight differences were noted, it is likely that differences in solubility in the micelle affect concentration at the polymerization site and thus modify the final content of the third monomer in the polymer. Different crosslinking reactions are used with various... 

Polymerization. Copolymers of tetrafluoroethylene/perfluoro(methyl vinyl ether) and the nitrile (1-4 mole ) have been prepared batch-wise in a stirred autoclave using an aqueous ammonium persulfate or ammonium persulfate-sodium sulfite redox couple system at 40°-100° C. The TFE/PMVE gas mixture was pressured, as required, to maintain the pressure and the nitrile pumped in solution in trichlorotrifluoro-ethane. After completion of the reaction, polymer was isolated from the latex (25-30 solids) by coagulation using ethanol and aqueous magnesium chloride solution. It was washed with alcohol/water solutions and dried at 70 °C in an oven under nitrogen. Mass balance indicated that most of the nitrile had been incorporated. 

The free-radical homopolymerization of vinyl ether monomers can be accomplished using various peroxide [131], azo [132], and redox initiators [133]. Polymerization under free-radical conditions gives only low-molecular-weight oligomers which have reported uses as... 

Besides vinyl acetate monomer, three other components are neeessary to earry out an emulsion polymerization water, an emulsifier and/or a proteetive eolloid, and a water-soluble initiator. Most commonly, anionic long-chain alkyl sulfonates are used as surfactants in amounts up to 6%. Studies have shown that the rate of polymerization is dependent on the amoimt of emulsifier present, with the rates inereasing as the amoimt of emulsifier is increased up to a certain point and then falling olF as free-radieal ehain transfer to the surfaetant beeomes a serious competing side reaetion [240]. In general, surfactants are used in eombination with a protective colloid. Especially useful as protective colloids are poly(vinyl alcohol), hydroxyethyl cellulose, alkyl vinyl ether-maleic anhydride and styrene-allyl alcohol copolymers, and gum arable. Water-soluble initiators, particularly potassium persulfate, alkali peroxydisulfates, hydrogen peroxide, and various redox systems, are most commonly used. 

The redox polymerization [(NH4)2S20g + NaHS03] at 50 C of 2-chloro-ethyl vinyl ether has been claimed [34]. 

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