LIQUID-CRYSTALLINE EPOXY-RESINS BY POLYADDITION OF DIGLYCIDYL ETHER OF 4,4'-DIHYDROXYBIPHENYL AND DIFUNCTIONAL AROMATIC-COMPOUNDS

This work is a continuation of the authors' earlier investigations of liquid crystalline epoxy resins prepared from diglycidyl ether of 4,4' -dihydroxybiphenyl (DGE-DHBP), which was used as a mesogenic agent, an d aliphatic dicarboxylic compounds, which were used as flexible spacer s. In this paper, the synthesis and characterization of liquid crystal line epoxy resins, prepared from DGE-DHBP and difunctional aromatic co mpounds are described. Three series of liquid crystalline epoxy resins were prepared by chain extension of DGE-DHBP with isomeric hydroxyben zoic and benzene-dicarboxylic acids as well as diphenols. An isophthal ic-terminated polyether was applied to decrease the temperature of pha se transitions. The syntheses were carried out by catalytic polyadditi on in the melt. Triphenylphosphine was applied as the catalyst. The re sulting epoxy resins were investigated by DSC, polarizing microscope a s well as by X-ray and IR spectroscopy. The phase transition temperatu res and the type of mesophase of the resulting products depend on the character of the functional groups in the chain extender and on the po sition of the functional groups in the aromatic ring. (C) 1998 John Wi ley & Sons, Inc.