Synthesis and properties of peroxy derivatives of epoxy resins based on bisphenol A. 1. Effects of the presence of inorganic bases

Oligomers containing peroxy groups have been synthesized from epoxies and a liphatic and aromatic hydroperoxides. The dependence of reaction rates upon ratios of starting materials, the presence of an inorganic base as a catal yst, nature of solvent, quantity of water, and temperature have been invest igated. The hydroperoxide + epoxy reactions proceed very slowly in the pres ence of NaOH but at satisfactory rates In the presence of KOH. The reaction s do not proceed in acetone, methylethylketone, dioxane, or toluene, but do proceed in secondary and tertiary alcohol media. We have studied in partic ular the reaction between tert-butyl-hydroperoxide (tBHPO), diglycidyl ethe r of diphenylpropane and an epoxy resin based on Bisphenol A and epichloroh ydrin. Structures of the products were confirmed by LR and H-1-NMR spectros copy. Mechanisms of reactions have been defined and an empirical equation t hat describes kinetics of the reaction between tBHPO and the epoxy has been developed. The peroxy oligomers so obtained were used to create networks b ased on a polyesteric resin. Going from 10 wt% of the peroxy oligomer to 25 % increases significantly the rate of gelation as well as the final gel wei ght fraction. However, a further increase of the peroxy oligomer concentrat ion to 50% affects only slightly the gelation kinetics and the plateau gel fraction.