Evaluation of the chain, length distribution in free-radical polymerization, 1 - Bulk polymerization

A method for the direct computation of the, chain length distribution in a bulk. polymerization is developed, based on the discretization, procedure introduced by Kumar and Ramkrishna (Chem. Eng. SA 1996,51, 1311) in the context of particle size. distribution. The overall distribution of chain,lengths is partitioned into a finite number of classes which are supposed to be concentrated at some appropriate pivotal chain, lengths. Several, of the involved reactions lead to the., formation, of chain whose length differs from the pivotal values. Rules have, been introduced in order to share chains between two contiguous classes, which have been designed so as to preserve two well-defined properties of the distribution, such as, for example, two of. its moments. The, method has been applied to a polymerization system, including propagation, bimolecular terminations and two different chain branching mechanisms: chain transfer to polymer and crosslinking. In addition, complex system such a one with chain rigth-dependent kinetic constants or a.two-dimensional distribution of chain length and number of branches have been considered