Recent progress in bulk polymerization: spatiotemporally discontinuous change of polymerization accompanied by phase separation

Abstract

Bulk polymerization converts liquid monomers into polymeric materials through an exothermic reaction, often leading to vitrification or the formation of highly viscous polymer melts depending on the monomer chemistry. It has long been assumed a priori that the polymerization solution remains homogeneous throughout the reaction process. Recent advances have revealed that apparent phase separation takes place near the polymerization-induced vitrification, and this event is closely linked to sudden reaction acceleration (i.e., the Trommsdorff effect) during bulk polymerization. Insights from recent studies on amorphous structure evolution have provided new perspectives on how local heterogenization affects reaction kinetics. This review summarizes recent progress in understanding bulk polymerization, with a focus on sudden reaction acceleration, and discusses the potential outcomes of the novel view.