Polymerization of vinyl chloride in the presence of crosslinking agents

Vinyl chloride was polymerized in the presence of a small quantity of such crosslinking agents as diallyl esters and divinyl ethers in a suspension and an emulsion system, in order to prepare poly(vinyl chloride) having very high polymerization degree. In the case of suspension polymerization, the average polymerization degree increased at first and decreased thereafter, via the maximum with the formation of gel, as the amount of crosslinking agent was increased. In the case of emulsion, however, when diallyl esters were used, the average polymerization degree changed in the same manner as in suspension without formation of gel. But divinyl ethers showed no effect on polymerization degree or gel formation. The difference of the effect of crosslinking agents on average polymerization degree and gel formation was discussed in both suspension and emulsion polymerization systems.