Pseudo-living radical polymerization of vinyl halide chain transfer agent and method of making agent

摘要

The present invention to a method of synthesizing poly(vinyl halide) by means of a free radical polymerization which mimics a "living" radical polymerization in the presence of an iodine containing chain transfer agent containing at least one iodine atom bonded to a primary carbon atom and having the formula:        R-CH₂ I     (I)        R-CHX I     (II),        R-CH(X)-CH₂ I     (III),        R-CH(X)-CHX I     (IV), or        R-CH(X)-CH₂-CHX I     (V),wherein X is fluorine, chlorine, bromine, or iodine, R is hydrogen, C₁, C₂, C₃, C₄, C₅ alkyl, any of which are linear or branched, cyanoalkyl, cyclohexyl, methyl cyclohexyl, phenyl, benzyl, and halogenated or oxygenated derivatives thereof.;In accordance with the invention there is further provided a method of synthesizing 1-halo-1-iodoethane by reacting hydrogen iodide with vinyl chloride or vinyl fluoride in the presence of an iodine generating catalyst under certain specified conditions. The resulting product of the reaction is a high yield, high purity 1-chloro-1-iodoethane or 1-fluoro-1-iodoethane. The poly(vinyl halide) resin is obtainable under conventional temperatures of polymerization and the chain transfer agents included herein perform consistently over repeated runs, hence useful for commercial manufacturing. The resin obtained has reduced molecular weight and polydispersity, good thermal stability, and enhanced mechanical properties, compared to poly(vinyl halide) conventionally formed by free radical methods at higher temperatures and/or with the use of conventional chain transfer agents for vinyl halide polymer.