Etude des prépolymères époxydes par chromatographie et ¹H NMR à 350 MHz

Abstract

Abstract The epoxy resins (DGEBA) obtained from 4,4′‐isopropylidendiphenol (bisphenol A) and 1‐chloro‐2,3‐epoxypropane (epichlorohydrin) and synthetized by the “taffy” process were found to consist of oligomers. The composition of prepolymers could be deduced from gel permeation chromatography (GPC), and particularly by high pressure liquid chromatography (HPLC). In the more resolved HPLC spectrum each oligomer was found to be accompanied by satellite peaks. The functionality of the prepolymers, determined by 1 H NMR spectroscopy and cryometric or vapour pressure osmometric measurements was found to be less than two. These phenomena are due to the existence of abnormal chain ends having no epoxy group. The structure of the main components spearated by preparative GPC was studied by 1 H NMR. For the impurities, the two indentified structures of chain ends are primary and secondary alcohol functions. Finally the compositions of three DGEBA were determined.