Synthesis of liquid crystalline epoxy and its mechanical and electrical characteristics - Curing reaction of LCE with diamines by DSC analysis

An aromatic liquid crystalline epoxy monomer based on biphenyl mesogen was synthesized and cured with three different aromatic diamines. The curing reaction characteristics were analyzed by DSC, and the data were introduced to the Kissinger equation to attain the kinetic parameters. Diglycidyl ether of 4,4'-biphenyl (DGEBP)/ 4,4'-diaminobiphenyl (DABP), and DGEBP/4,4'-methylenediamine (MDA) systems showed an exotherm curing reaction after comelting of the monomers; the DGEBP/p-phenylenediamine (PDA) system's curing reaction took place in the solid state without melting of monomers. The activation energy and preexponential factor for the DGEBP/ DABP system were 55.6 kJ/mol and 4.0 X 10(6) min(-1), respectively. Those values for DGEBP/MDA and DGEBP/PDA systems were 55.1 kJ/mol and 1.0 X 10(6) min(-1) and 148.8 kJ/mol and 7.7 X 10(19) min(-1), respectively. The rate constant at 100degreesC for DGEBP/PDA is 2 times higher than those for DGEBP/DABP and DGEBP/MDA, which have almost the same values. Strictly speaking, the rate constant of DGEBP/DABP is a little higher than that of DGEBP/MDA, and these results are in good agreement with the DSC curves. (C) 2002 John Wiley Sons, Inc.