Control of Intermolecular Cross-Linking Reaction in Free-Radical Cross-Linking Monovinyl/Divinyl Copolymerizations by the Aid of Amphiphilic Nature of Primary Polymer Chains and Cross-Link Units with Opposite Polarities

Abstract

The control of the intermolecular cross-linking reaction in free-radical cross-linking monovinyl/divinyl copolymerizations resulting in amphiphilic network polymers was attempted by the aid of amphiphilic nature of primary polymer chains and cross-link units with opposite polarities. First, benzyl methacrylate (BzMA)/tricosaethylene glycol dimethacrylate (PEGDMA-23) (95/5) copolymerizations in 1,4-dioxane (DO) and DO/H2O (85/15) mixed solvent were investigated. The assembly of short primary polymer chains induced the restricted motion of propagating polymer radical, leading to a suppressed increment of molecular weight with conversion. Second, 2-hydroxyethyl methacrylate (HEMA)/henicosapropylene glycol dimethacrylate (PPGDMA-21) (95/5) copolymerizations in DO, DO/H2O (80/20) mixture, and DO/H2O (70/30) mixture were explored. The assembly of nonpolar cross-link units led to an enhanced occurrence of intermolecular cross-linking reaction. Moreover, the assembly of polar primary polymer chains consisting of ...