UV-Initiated Bubble-Free Frontal Polymerization in Aqueous Conditions

From an industrial point of view the-most interesting Method of bulk curing of acrylate-based monomers is a thermal frontal reaction initiated by the application of UV-light. In water-based systems, UV triggering of bubble-free thermal front reactions is difficult to realize as solvent boiling and decomposition of the thermal initiator lead to uncontrollable heat loss, porous polymer samples, and expansion of the formulation. Especially bubble formation in the light-exposed area causes diffuse light scattering and as a result nonreproducible investigation of the UV initiation. Within this work a new thermal initiator has been synthesized, allowing us to report a bubble-free steady-state thermal front reaction in water. The new system allowed us to achieve a well-Observable front reaction and provided the basis for an accurate and reproducible, systematic analysis of UV initiation in water-based frontal polymerizations, considering the ratios of all reactive components.