Polythioethers bearing side groups for efficient degradation by E1cB reaction: reaction design for polymerization and main-chain scission.

We have previously reported the polycondensation by the tandem reactions of dithiols and α-(bromomethyl)acrylates, consisting of conjugate substitution (S2' reaction) and conjugate addition (Michael addition) reactions. The resulting polythioethers underwent a main-chain scission (MCS) by E1cB reaction, which is the reverse reaction of conjugate addition, although it was not quantitative due to the equilibrium. Herein, the modification of the structures of polythioethers led to irreversible MCS, whereby the β-positions of ester moieties were substituted with a phenyl group.