Synthesis and characterization of liquid crystalline epoxy with cholesteric structure for modification of epoxy resin

摘要

A novel liquid crystalline epoxy resin, 4-(4-oxiranyl-methoxyl)-benzoicacid cholesterol ester (OAC), is synthesized and characterized by spectroscopic techniques. The mesogenic behavior of the monomer is measured by polarized optical microscopy (POM); OAC presents various textures in the range of 130-215 degrees C. The curing behavior of OAC with 1,4-phenylenediamine is investigated by means of differential scanning calorimetrty(DSC), POM, and wide-angle X-ray diffraction (WAXD). Information about distribution of OAC in blend system results from FT-IR Imaging System, indicating molecules of OAC can agglomerate to form anisotropic domains. The improvement of mechanical properties of Diglycidyl Ether of Biphenol A (DGEBA) modified with OAC has been achieved. Scanning electronic microscopy shows that extremely rough and highly deformed fracture surface can be obtained. Moreover, the influence of the concentration on the glass transition temperature has been characterized by dynamic mechanical analysis (DMA).