Postgel properties in the statistical crosslinking of heterochains. I. Systems with N types of chains

The heterochain crosslinking model describes nonrandom crosslinking of poly mer chains and is an extension of the classical Flory/Stockmayer gelation t heory. We consider the postgelation relationship for the system consisting of N types of polymer chains, in which the probability that a crosslink poi nt on an i-type chain is connected to a j-type chain is explicitly given by p(ij). The analytical solutions for the weight fraction of the sol, the nu mber-average and weight-average molecular weights within the sol fraction, and the crosslinking density within the sol and gel fractions are derived f or the systems, with each type of chain conforming to the Schulz-Zimm distr ibution. Illustrative calculations are shown for the systems consisting of two and three types of chains, and the obtained results agree with those fr om the Monte Carlo method. (C) 2000 John Wiley & Sons, Inc.