Evolution of isothermal polymerization fronts via laser line deflection and predictive modeling
Isothermal frontal polymerization (IFP) is a self-sustaining, directional polymerization that can, be used to produce gradient refractive index materials. Accurate detection of frontal properties has been difficult due to the concentration gradient that forms from the diffusion and subsequent polymerization of the monomer solution into the polymer seed. A laser technique that detects tiny differences in refractive indices has been modified to detect the various regions in propagating fronts. Propagation distances and gradient profiles have been determined both mathematically and experimentally at various initiator concentrations and cure temperatures for IFP systems of methyl methacrylate with poly(methyl methacrylate) seeds and with the thermal initiator 2,2'-azobisisobutryonitrile.