Fully degradable polymer networks from conventional radical polymerization of vinyl monomers enabled by thionolactone addition

Abstract

We report the preparation of degradable polymer networks by conventional free radical copolymerization of n-butyl acrylate with a crosslinker (1 mol%) and dibenzo[c,e]oxepane-5-thione (DOT) as a strand-cleaving comonomer. Addition of only 4 mol% of DOT imparts the synthesized networks with full degradability by aminolysis, whereas gels with less DOT (2-3 mol%) cannot be degraded, in excellent agreement with the recently proposed reverse gel-point model. Importantly, even though DOT significantly slows down the polymerization and delays gelation, it has a minimal effect on physical properties of the networks such as shear storage modulus, equilibrium swelling ratio, glass transition temperature or thermal stability.

Fully Degradable Polyacrylate Networks from Conventional Radical Polymerization Enabled by Thionolactone Addition

“…Additionally, the very recent work by Johnson et al showed recyclability of DOT-containing polystyrene and could potentially be extended to crosslinked systems offering a way to circular vinyl thermosets. We therefore expect increased interest in thionolactones for the preparation of degradable networks …”