Curing and Alignment of Liquid Crystalline Epoxy Networks

Abstract

ABSTRACTLiquid crystalline epoxy networks have been prepared from glycidyl terminated polyether oligomers of varying molecular weight. These oligomers were prepared by functionalizing hydroxy terminated oligomers based on 4,4'- dihydroxy-α-methylstilbene and α,ω-dibromoalkanes with glycidyl groups. Curing of these oligomers was carried out either within their nematic mesophase or in their isotropic state. Different thermal properties were observed after curing under these two sets of conditions. Extremely low values of the coefficient of thermal expansion in the range of 15 to 60 ppm/°C were achieved. To produce aligned thermosets, orientation of the liquid crystalline phase was induced during the curing process by a magnetic field. Orientation of these networks was measured by wide angle x-ray diffraction (WAXD).