Frontal polymerization in microgravity

Frontal polymerization is a mode of converting monomer into polymer via a localized reaction zone that propagates through the coupling of thermal diffusion and Arrhenius reaction kinetics. Because of convective instabilities, it is not possible to perform frontal polymerization with many monomers that produce thermoplastics, such as n-butyl acrylate, without the addition of a viscosity enhancing agent. Sounding rocket experiments allowed the preparation of benchmark materials and demonstrated that methods to suppress the Rayleigh-Taylor instability in ground-based research did not significantly affect the molecular weight of the polymer. The interaction of bubbles with propagating fronts with liquid product and solid product was studied on KC-135 flights. Bubbles aggregate in microgravity but are dispersed in 1 g.