A comparative study on 3D printed silicone-epoxy/acrylate hybrid polymers via pure photopolymerization and dual-curing mechanisms

A type of silicone-epoxy resin has been synthesized and compounded with acrylates to obtain hybrid inks for stereolithography 3D printing. Two approaches of printing have been developed: one approach is pure photopolymerization through the addition of free radical and cationic photoinitiators to the hybrid resin; the other approach untilizes a photo-thermal dual-curing system with free radical photoinitiator for acrylates and thermal curing agent for epoxy resin. The results of hardness, gel content, FTIR and SEM measurements show that both systems get highly crosslinked and interpenetrating polymer network structures, but with different extent of phase separation due to different curing processes. Thermalmechanical and mechanical tests demonstrate that 3D objects from the dual-curing system have higher glass transition temperatures, higher printing efficiency and much enhanced mechanical properties compared with these from the pure photopolymerization system. In addition, both of the systems get 3D objects with high printing accuracy and good thermal stability. The dual-curing mechanism, therefore, has distinct advantages over the pure photopolymerization method.