Photocuring of Radically Polymerizable Hyperbranched Polymers Having Degradable Linkages

Abstract

Hyperbranched polymers having a number of reductive disulfide bonds and radically reactive vinyl groups were synthesized by the bulk radical homopolymerization of bis(2-methacryloyloxyethyl)disulfide (disulfide based dimethacrylate, DSDMA) as a divinyl monomer in the presence of methyl 2-(bromomethyl)acrylate as an additionfragmentation chain transfer agent.The resulting hyperbranched polymers (HBDSDMAs) were photocured by irradiated at 365 nm in the presence of 2,2-dimethoxy-2-phenylacetophenone as a photo radical initiator. The photocured HB-DSDMA exhibited high transparency in the visible region and good solvent resistance for various organic solvents.Reduction of the disulfide groups smoothly proceeded in the presence of tributylphosphine as a reductant, and the cured HB-DSDMAs were completely solubilized. HB-DSDMAs were also photocured by irradiation at 254 nm due to the homolysis of the disulfide groups with subsequent initiation of the radical polymerization.

Cross-linked Polyperoxides for Photoremovable Adhesives

“…Cross-linked polymers containing degradable groups such as tertiary esters and tertiary carbonates [15][16][17], Diels-Alder adduct moieties [18,19], acetal group [20], disulfide bond [21][22][23], and peroxy bond [24][25][26][27] are one class of candidates for dismantlable adhesives.…”