Thermosetting matrices for composite materials based on allyl/propagryl substituted novolac resins

Abstract

A new type of modified thermoset resins was synthesized by Williamson reaction from novolac resin and a mixture of allyl and propargyl chlorides of the different ratios with total allyl/propargyl substitution 50 %. The compositions of the resins were defined by nuclear magnetic resonance (1H NMR) spectroscopy, and the dependence of the cured material properties on the composition was established. An increase of a propargyl content resulted in char yield raise, and the maximum value had been found for propargylated resin which was 60 %. By differential scanning calorimetry (DSC) analysis of the curing process, it was demonstrated that exothermic enthalpy could be adjusted by varying the content of propargyl and allyl groups in the resin. It was shown that the resin substituted with allyl only ether could not be cured without decomposition, but an introduction of propargyl groups in allyl ether-modified resin allowed to obtain cured samples and thus to develop a new type of thermosetting resins.