Microgel formation in emulsion polymerization

A typical behavior of microgel formation in emulsion polymerization, where a sufficient amount of crosslinker exists and no coagulation of particles o ccurs, is considered both theoretically and experimentally. It was found th at the crosslinked polymer formation in emulsion polymerization is signific antly different from that in homogeneous media. The important characteristi cs can be summarized as follows. (1) The crosslinking density level is fair ly high even from very early stages of polymerization, (2) the weight-avera ge molecular weight increases just linearly with monomer conversion, and (3 ) the formed molecular weight distribution (MWD) is rather narrow and the d istribution shifts to larger molecular weights with preserving the narrow p rofile as polymerization proceeds. In a typical microgel formation in emuls ion polymerization, each polymer particle essentially consists of a single crosslinked polymer molecule once stable polymer particles are formed. (C) 1999 Elsevier Science Ltd. All rights reserved.