FOURIER-TRANSFORM INFRARED-ANALYSIS OF A LINEAR, ANHYDRIDE-CURED EPOXY

A linear-chained epoxy resin was formulated from phenyl glycidyl ether and nadic methyl anhydride catalyzed by benzyldimethylamine. Intermol ecular polymerizations were modeled as a parallel set of propagation r eactions. Fourier-transform infrared spectroscopy was used to determin e the concentrations of the oxirane, anhydride, and ester moieties wit hin the resin as a function of time for two isothermal cures. Data ana lyses yielded the propagation rate constant as a function of temperatu re and the initiator's concentration, including contributions from imp urities within the resin. Results compared favorably with measurements on fractionated resins, using gel permeation chromatography. Populati on density distributions are described by Poisson molar distributions for this resin.