Curing kinetics of acrylate-based and 3D printable IPNs

Abstract

In this work, the kinetics of curing of a new family of interpenetrating polymer networks (IPNs) obtained by co-formulation of a photocurable acrylic resin with a thermocurable epoxy/anhydride mixture is studied. The first curing stage is an acrylate free-radical photopolymerization at ambient temperature, and the second curing stage is an epoxy-anhydride copolymerization initiated with a nucleophilic tertiary amine at higher temperatures. The presence of a diperoxyketal thermal radical initiator added to the liquid formulation facilitates uniform and complete acrylate conversion during thermal second curing stage and opens the possibility of curing the same materials by thermal curing only. The thermal curing kinetics was studied by integral isoconversional and model fitting procedures, whereas photocuring kinetics was satisfactorily fitted to a first order expression. Thermal curing and storage stability at room temperature were successfully simulated by using the isoconversional kinetic parameters. These ternary formulations have potential as 3D printable thermosets.