A novel condensation-addition-type phenolic resin (MPN): Synthesis, characterization and evaluation as matrix of composites

This paper reports a novel methylol and propargyl-containing dual-cure-mechanism novolac-based phenolic resin (MPN). MPN resins with varying contents of reactive groups were synthesized by a two-step one-pot method facilly and characterized by Flourier transfer infrared spectra (FT-IR), hydrogen magnetic resonance spectra (¹H NMR), gel permeation chromatography (GPC), dynamic scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) techniques. The resins could be thermally cured by two gradual but fused stages: Condensation of methylol groups and addition polymerization of propargyl groups. This novel resin has advantages over conventional condensation-cure and addition-cure phenolic resins in processing capability. The results of DMA and thermogravimetry analysis (TGA) showed the cured resins possessed high thermal properties. Evaluation of MPN as matrices for advanced composites indicated the enhanced crosslink network derived from dense reactive groups in one single molecule was beneficial to the admirable thermal stability, but was detrimental to the mechanical properties of the resultant composites. MPN resin was amongst ideal candidates for matrices of high temperature materials.