Search for: All records

A model was developed to help predict how enzymes can be used to temporally control the gelation of polyvinyl alcohol (PVA) with borate.

Frontal polymerization (FP) of epoxy monomers is typically achieved with a radical‐induced cationic frontal polymerization (RICFP) process that combines a thermal radical initiator with an onium salt superacid generator. In this paper, we show that both thermal and UV‐initiated cationic frontal polymerizations are possible for common epoxy and vinyl ether monomers with only an iodonium superacid generator in the absence of a standalone thermal radical initiator. Increasing superacid generator concentration resulted in an increase in front velocity, as did the addition of vinyl ether to epoxies. The front velocity is reduced by the addition of 4‐methoxyphenol (MeHQ), indicating free‐radicals play a significant role.

Formulations containing vinyl ethers and epoxy were successfully polymerized through a radical‐induced cationic frontal polymerization mechanism, using an iodonium salt superacid generator with a peroxide thermal radical initiator and fumed silica as a filler. It was found that an increase of vinyl ether content resulted in higher front velocities for divinyl ethers in formulations with trimethylolpropane triglycidyl ether. However, increased hydroxymonovinyl ether either decreased the front velocity or suppressed frontal polymerization. The kinetic effects of the superacid 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 system exhibiting higher sensitivity to the superacid generator concentration.