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.

Frontal polymerization (FP) is a process in which a front propagates in a localized reaction zone, converting monomer into polymer through the coupling of thermal diffusion with the Arrhenius kinetics of an exothermic reaction. Fillers are added to control the rheological properties of the formulation and to enhance the mechanical properties of the product. However, the thermal and chemical effects of these fillers on the front propagation have not been thoroughly explored. Herein we report the thermal and chemical effects of fillers on free‐radical frontal polymerization. It was found that fillers with high thermal diffusivities, such as milled carbon fiber and boron nitride increased the front velocity. Despite their high thermal diffusivities, fillers such as aluminum and alumina decreased the front velocity. This is likely due to the radical‐scavenging ability of aluminum oxide, which was explored with clay minerals. It was found that the presence of water within clay fillers can also decrease the front velocity. To probe the chemical effects, acid‐activated clay minerals were utilized. The results demonstrate that some fillers can increase front velocity through their high thermal diffusivities while others decrease it by acting as radical scavengers.

Frontal polymerization, which involves a self-propagating polymerizing reaction front, has been considered as a rapid, energy-efficient, and environmentally friendly methodology to manufacture lightweight, high-performance thermoset polymers, and composites. Previous work has reported that the introduction of thermally conductive elements can enhance the front velocity. As follow-up research, the present work investigates this problem more systemically using both numerical and experimental approaches by investigating the front shape, front width, and heat exchange when aluminum and cooper metal strips are embedded in the resin. The study reveals that the enhancement in the front velocity is mainly due to a preheating effect associated with the conductive element. Moreover, the numerical parametric study for the system size shows that the front speed increases as the system size decreases, ultimately approaching a prediction provided by a homogenized model for polymer–metal composites.

Frontal polymerization is a process in which a localized reaction zone propagates from the coupling of thermal transport and the Arrhenius rate dependence of an exothermic polymerization; monomer is converted into polymer as the front passes through an unstirred medium. Herein we report the first study of

The kinetics of photopolymerization in deep eutectic solvents (DESs) is investigated through real‐time Fourier transform‐infrared spectrometry (RT‐FTIR). The systems of this study are choline chloride (ChCl) DESs made of acrylic acid and methacrylic acid (DES monomers) and a nonreactive analog isobutyric acid (IBA). The DES consisting of the analog also contains the monomer methyl methacrylate (MMA). Analysis of the evolution of conversion indicates dramatic increase in polymerization rate when comparing the polymerization of the DES monomers to pure monomer polymerization. A significant increase in polymerization rate is also seen in the systems that include a methyl ester derivative of the hydrogen bond donor monomer (e.g., MMA) in a nonpolymerizable DES (e.g., IBA−ChCl). It is proposed that the increased solvent viscosity, preorganization due to hydrogen bonding, and the polarity of the DES around the monomers play a role in the enhancement of the polymerization rate.