Frontal polymerization (FP) is a phenomenon in polymer science where an input of energy initiates a reaction zone that propagates through a material, converting monomer to polymer as it travels. FP has advantages such as the ability to synthesize materials in a cure-on demand, one-pot system. Thermal FP is initiated by thermal energy and relies on the kinetics of an exothermic reaction coupled with heat diffusion. Formulations containing vinyl ethers and an epoxy were successfully frontally polymerized thermally through a radical-induced cationic frontal polymerization mechanism, using an iodonium salt superacid generator with a peroxide thermal radical initiator. Fumed silica was added as a filler to supress front-quenching buoyancy-driven convection. Once a propagating front reaches a steady state, the speed at which a front travels can be observed (front velocity), which is a result of the system’s reactivity. It was found that an increase of vinyl ether content resulted in much higher front velocities for vinyl ethers in formulations with an epoxy than systems containing epoxy alone. The kinetic effects of the acid generator and thermal radical initiator with varying vinyl ether content were also studied. It was observed that increasing concentrations of initiators increased the front velocity, with the vinyl ether system exhibiting higher sensitivity to the acid generator concentration. This work confirmed that vinyl ethers are frontally polymerizable through cationic mechanisms and the addition of vinyl ethers to systems will cause stark increases in front velocity.

Addition of highly reactive vinyl ethers in radical-induced cationic frontal polymerization

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.