New novolac-based polytriazole resins and their composites

A kind of novolac-based polytriazole (NPTA) resins was designed and synthesized from propargyl-functionalized novolac resin and diazides. The rheological properties, curing behavior and thermal properties of the novolac-based polytriazole resins were studied. The NPTA resins were also evaluated as the matrix for carbon fiber reinforced composites. The results reveal that the NPTA resins have good processiblity. The initial curing temperature is under 80℃, while the activation energy for the cross-linking is higher than the reported linear polytriazoles. The chain structures have little effect on the rheological properties, curing behavior and apparent activation energy of curing reaction of the NPTA resins. However, the thermal properties of the cured resins are greatly influenced by the structure of the crosslinked backbone. The glass transition temperature of the resins arrives at as high as 278℃. The flexural strengths of the T700 carbon fiber-reinforced NPTA composites (T700/NPTA) at ambient temperature reach the value higher than 1 590 MPa and their retention rates at 150℃ stand over 68.6%.