INFLUENCE OF MOLECULAR-STRUCTURE ON THE FREE-RADICAL INITIATED NETWORK POLYMERIZATION OF DIMETHACRYLATES

The free radical polymerization of several new dimethacrylates initiat ed by azobisisobutyronitrile (AIBN) at various temperatures was invest igated by differential scanning calorimetry (DSC), Fourier transform i nfrared (FT-IR), and solid state NMR. The new monomers contained featu res, such as fluoroalkyl and/or pendant methyl or hydrogen instead of hydroxyl groups, which promoted both low viscosity and low monomer gla ss transition temperatures. The percent conversion was significantly i mproved, relative to a well-studied control dimethacrylate as measured by both DSC and FT-IR. Increasing the reaction temperature and the in itiator concentration also led to enhanced conversion behavior and the apparent activation energies for the polymerization are reported. The results suggests that the new crosslinked material systems could show several advantages relative to the control bisphenol-A based diglycid yl methacrylate.