Free radical branching homopolymerization of asymmetrical divinyl monomers in isopropyl alcohol

Abstract

The radical polymerization of multivinyl monomers usually provides crosslinking polymers. It is a significant challenge how to control the structure of the polymers and to obtain soluble polymers in a high yield. In this work, the radical branching polymerizations of two asymmetrical divinyl monomers, allyl methacrylate (AMA) and furfuryl methacrylate (FMA), were investigated in detail. Both of the reactivity of the bonds and the weak transfer of isopropyl alcohol (IPA) were used to control the development of branching polymerizations and avoid gelation, without any other additives. As a result, the soluble branched PAMAs and PFMAs with extremely high molecular weights (106∼107) were successfully obtained. The branching factor (g’) of PAMA is very low (0.01–0.02), and that of PFMA is the higher (about 0.3) due to the weaker reactivity of furfuryl groups. Comparing with the results of using thiol chain transfer agent, the chain transfer of IPA had no obvious influence on the chain propagation at the early stage of the polymerizations, but could delay the gelation successfully at the later stage. Furthermore, the development of the branching structure could be studied in detail on the branching factor and rms radius since the gelation process was extended from several minutes to several hours.