Determination of the effects of cure conditions on the photopolymerization of liquid crystalline monomers using differential photo-calorimetry

Photopolymerization of diacrylate liquid crystalline monomers has several advantages over thermal polymerization. Most notably, photopolymerization allows for the cure reaction to occur at a temperature where a mesophase exists. In this paper we discuss the effects of several cure conditions, including temperature, on the conversion and reaction rates of two liquid crystalline monomers. Each of these monomers exhibits a nematic mesophase at elevated temperatures. The data indicate that the presence of the mesophase has an impact on both reaction rates and conversion. Further studies concerning the effects of photoinitiator composition and concentration reveal that these parameters significantly influence the polymerization rate but do not affect the degree of conversion at extended irradiation times.