MOLECULAR-WEIGHT DISTRIBUTIONS AND MOMENTS FOR CONDENSATION POLYMERIZATIONS CHARACTERIZED BY 2 RATE CONSTANTS

Molecular weight distributions (MWD) and moments have been computed for condensation polymerizations of ARB-type monomers wherein the reactions involving the monomer are characterized by a rate constant k11 and those involving other species, by kp. For k11/kp < unity, the MWD curves are found to split into two, one for even n and one for odd values of n. Substantial amounts of unreacted monomer are found in the reaction mass for this case and so moments and the polydispersity index computed without the monomer are better representations of the distributions. For k11/kp > unit, conventional MWDs are observed with dispersions different from those representing polymerizations satisfying the equal reactivity hypothesis. © 1979.