COPOLYMERIZATION WITH CHAIN TRANSFER MONOMER .1. DISTRIBUTION OF BRANCH-POINTS

A theoretical investigation is conducted on a batch free-radical copol ymerization in which one type of monomer possesses a high chain transf er constant with a polymerizable double bond in it, which is called th e chain transfer monomer. When the chemical structures of the polymeri zable double bonds are the same for the monomer pair, the reactivity r atios may be close to unity. In such cases, the probability of possess ing a branch point may become the same for all units bound to polymer molecules at any stage of polymerization, irrespective of the magnitud e of the chain transfer constant. On the other hand, a homogeneously b ranched structure cannot be formed except when the chain transfer cons tant is unity, because the primary chains formed at different stages o f polymerization are not connected randomly. The present reaction syst em could be used to investigate the effect of detailed structural diff erences on the physical properties of branched polymer systems.