Addition-curable propargyl-containing novolac-type phenolic resin: Its synthesis, characterization, cure, and thermal properties

In this article, propargyl functionalized novolac resins (PN resins), with varying propargyl contents and varying molecular weights, were synthesized conveniently. The structural characteristics were determined by 1HNMR and FTIR methods. Thermal cure studies revealed that the uncatalyzed thermal cure was remarkably affected by propargyl extent, while it was hardly affected by molecular weight. The processability of the as-prepared PN resins was excellent as matrix of composite materials. The cure mechanism was complicated; postcure at high temperature was required to achieve entire crosslink formation. Both dynamic mechanical analysis and thermogravimetric analysis showed that the cured PN resins had substantially improved thermal mechanical properties and thermal stability in comparison to conventional cured phenolics. High propargyl extent was preferred for high thermal stability. The results show that PN resin is one of the ideal candidates for advanced composites matrices in thermostructural and ablative applications. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1010–1017, 2006