LIQUID-CRYSTALLINE EPOXY-RESINS BY POLYADDITION OF ALIPHATIC DIEPOXIDES WITH 4,4'-DIHYDROXYBIPHENYL

Liquid crystalline epoxy resins were synthesized from 4,4'-dihydroxybi phenyl (DHB), which was used as a mesogenic component, and diglycidyl ethers of aliphatic glycols (ethylene glycol and 1,6-hexanediol) which were used as flexible spacers. The synthesis was carried out by the c atalytic polyaddition in the melt. Triphenylphosphine was used as the catalyst. The course of the polyaddition was investigated at various m olecular ratios of the reactants. It was found that both linear and br anched structures were formed in the course of the synthesis. The rate s of the formation of the structures were calculated. The epoxy oligom ers were investigated by DSC, polarizing microscope, and x-ray and IR spectroscopy. The molecular weight distribution was determined by GPC. The dependence of liquid crystalline properties of the obtained epoxy resins on the molecular weight and on the chain length of the flexibl e spacer was investigated. The molecular weight of the epoxy oligomers and the length of flexible spacer influence the phase transition temp eratures. (C) 1995 John Wiley and Sons, Inc.