Studies On Synthesis And Curing Reaction Of Liquid Crystalline Epoxy

Liquid crystalline polymer is a kind of material of construction and function with excellent properties and wide applications. Liquid crystalline epoxy is an important kind of liquid crystalline thermoset. The aims of this study on synthesis, curing reaction of liquid crystalline epoxy and modifying of epoxy with liquid crystalline epoxy are to provide valuable instructions for development of liquid crystalline epoxy.Diglycidyl ether of 4,4'-dihydroxybiphenol(DGEBP) has been preared with a simple method of synthesis and purifying and characterized by FT-IR, DSC and POM. The liquid crystalline phase has been found when DGEBP was observed at 140℃ under the polarized optical microscope. The effect of synthesis conditions on liquid crystalline phase, epoxy equivalent and vield has been studied.Curing reaction of DGEBP has been studied. The development of liquid crystalline phase of DGEBP/DDM system when heating has been recorded with POM photos.Gel curve and Ea~a curve of DGEBP/DDM system has been plotted, and T_g under different curing temperature of DGEBP/DDM system has been got. All this data have been compared with those of E-51/DDM system. It has been considered that liquid crystalline phase improved curing reaction. Due to the structure of liquid crystalline, T_g of DGEBP/DDM system was higher than that of E-51/DDM system.E-51 has been modified with DGEBP. It has been found that the impact, tensile and bend strength and HDT and T_g of modified resin were raised with the increasing of the DGEBP content. TGA test has been conducted, and it has been found that the thermal decomposition temperature of modified resin rised with the increasing of DGEBP content.Ethylene glycol diglycidylether(EGDE) which is an important kind of intermediate tosynthesize liquid crystalline epoxy has been prepared. The chemical structure of EGDE has been characterized with FT-IR, and effect of synthesis conditions on epoxy equivalent and vield has been studied.