CHAIN COPOLYMERIZATION 6- 1 General Considerations

The consistent kinetic analysis of the copolymerization with the simultaneous occurrence of the reactions (2.1) and (2.5) leads to the conclusion that the probabilities of the sequences of the monomer units M, and M2 in the macromolecules can not be described by a Markov chain of any finite order. Consequently, in this very case we deal with non-Markovian copolymers, the general theory for which is not yet available [6]. However, a comprehensive statistical description of the products of the complex-radical copolymerization within the framework of the Seiner-Litt model via the consideration of the certain auxiliary Markov chain was carried out [49, 59, 60]. 

Copolymerization involves the simultaneous chain polymerization of a mixture of two or more monomers (Hillmyer, 2012 Ham and Alfrey, 1964 Odian, 2004a Tirrell, 1986). Aside from the general kinetic considerations which govern these chain reactions, as described earlier, there is imposed an additional... 

Copolymerization involves the simultaneous chain polymerization of a mixture of two or more monomers [89-92], Aside from the general kinetic considerations which govern these chain reactions, as described earlier, there is imposed an additional feature, i.e., the relative participation of the different monomers during the growth of the chain. This new parameter is most important, since it controls the composition of the copolymer. Systems involving more than two monomers are difficult to resolve in this respect, but it has been found possible to treat the case of a pair of monomers with relative ease [91,93-95]. 

Vinylphosphonates are slow to homopolsunerize. They copolymerize with most common monomers but particularly well with vinyl acetate (63), vinyl chloride, and acrylonitrile (64). The copolymerization Q and e values for bis(2-chloroethyl) vinylphosphonate are 0.23 and 1.73, respectively (65), reflecting an electron-poor double bond and low resonance stabilization of the free radical. They are also prone to chain transfer. Representative copolymers have been studied and evaluated for their expected flame-retardant action (66) but cost considerations have generally not encouraged commercial use of vinylphosphonate esters for this purpose. 

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