ALLYL MONOMERS AND POLYMERS

Another use is of minor proportions of polyfunctional aHyl esters, eg, diaHyl maleate, ttiaHyl cyanurate, and ttiaHyl isocyanurate, for cross-linking or curing preformed vinyl-type polymers such as polyethylene and vinyl chlotide copolymers. These reactions ate examples of graft copolymerization in which specific added peroxides or high energy radiation achieve optimum cross-linking (see Copolymers). 

Whereas vinyl acetate [108-05-4] upon heating with benzoyl peroxide or other free-radical initators, forms solid polymers of high molecular 

This is explained by the low reactivity of the double bond of the allyl compound together with prevalence of chain termination through reaction of allyhc H atoms as shown (2). 

When vinyl and aHyl monomers undergo chain transfer with solvents, so-caHed telomers may form, generaHy of rather low molecular weight (1). 

Because of the low reactivity and tendency to undergo chain transfer, small additions of most aHyl compounds retard polymerization of typical vinyl monomers ia free-radical systems (1,3) and may be useful ia controlling molecular weight and stmcture ia polymers. 

Small proportions of mono- or polyfunctional aUyHc monomers also may be added as regulators or modifiers of vinyl polymerization for controlling molecular weight and polymer properties. Polyfunctional aUyHc compounds of high boiling point and compatibiHty are employed as stabilizers against oxidative degradation and heat discoloration of polymers. DiaUyl ammonium salt copolymers are used in water purification and flocculation. Compounds 

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In this article, mainly monoallyl compounds are described. DiaHyl and triaHyl compounds used as monomers are covered in the article entitled Allyl MONOMERS AND POLYMERS and also in the hterature (36,37). 

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