Effect of feed rate on structure of hyperbranched polymers formed by self-condensing vinyl polymerization in semibatch reactor

Abstract

Hyperbranched polymers formed by a self-condensing vinyl polymerization, SCVP, of copolymerization of AB* monomers slowly added into trifunctional C*/sub 3/ cores under various feed rates were investigated by a kinetic model. The dependences of average molecular weight, polydispersity, degree of branching, and number of structural units of the hyperbranched polymers on the feed rate were calculated by a generating function method. It was found that the final polydispersity index, PDI, can be attained below 1.5 by a slow addition with the parameter of feed rate, /spl pi/, less than 2. While the AB* monomers fed quickly, the system with a lower content of the C*/sub 3/ cores results in a broader molecular weight distribution. A high degree of branching, about 0.66, can be achieved by addition of a small amount of C*/sub 3/ cores at /spl pi/ lower than 10.