The dependence of the structure of poly(vinyl chloride) on precipitation conditions during polymerization was investigated. Properties of polymers prepared in 2,4,6‐trichloroheptane, 2,4‐dichloropentane, sec ‐butyl chloride, and isohexane were compared. The character of the polymerization ranged from homogeneous to heterogeneous. The polymers were fractionated in the system tetrahydrofuran–water. Molecular weights of the fractions were determined by osmometry and light scattering in cyclohexanone and tetrahydrofuran. The ratio M̄ w / M̄ n of the fractions varied in the range 1.1–1.8. It was found that for all the polymers investigated the same relation between [η] and M̄ w is valid. Samples prepared by heterogeneous polymerization to a low conversion do not therefore exhibit an appreciable amount of branching with long side chains. These results are compared with the behavior of high‐conversion polymers and of branched samples prepared by copolymerization of vinyl chloride with divinyl adipate.
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Kolínsk et al. (1967) studied this question.
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