Influence of molecular structure on the free radical initiated network polymerization of dimethacrylates

The free radical polymerization of several new dimethacrylates initiated by azobisisobutyronitrile (AIBN) at various temperatures was investigated by differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR), and solid state NMR. The new monomers contained features, such as fluoroalkyl and/or pendant methyl or hydrogen instead of hydroxyl groups, which promoted both low viscosity and low monomer glass transition temperatures. The percent conversion was significantly improved, relative to a well-studied control dimethacrylate as measured by both DSC and FT-IR. Increasing the reaction temperature and the initiator 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 diglycidyl methacrylate.