The Synthesis of New Epoxy Resins and their Physical Properties

A series of homologous bisphenols was synthesized by the reaction of potassium p-hydroxy-benzoate with dichloroalkanes or by the esterification of p-hydroxybenzoic acid with glycols. The studies of the synthesis of the diglycidyl ethers from these bisphenols were carried out by variation of the reaction conditions. The diglycidyl ethers synthesized were cured with hexahydroxyphthalic anhydride or with 4,4′-diaminodiphenylmethane. The effects of chemical structure of the cured resins on their mechanical, thermal, electrical, and adhesive properties were investigated. The results show that there is a good correlation between chemical structure and physical properties of the cured resins. The more the number of oxyethylene units (‒O‒CH 2 ‒CH 2 ‒) that are incorporated into the bisphenol portion of the network, the more flexible and polar the cured resins become. The increase in the flexibility of the cured resins is manifested by the decrease in the deflection temperature, elastic modulus and the enhancement of the elongation of the resins. The increase in the polarity of polymer results in the enhancement of the electric constant and the better adhesive properties.