Study on the curing behavior of polythiol/phenolic/epoxy resin and the mechanical and thermal properties of the composites

Abstract

Phenolic/epoxy resin (EP-PF) composites were prepared, in which phenolic resin and epoxy resin was used as matrix, polythiol and triethanolamine as curing accelerators. The uniform experimental design method was used to obtain the scheme, in which the resin system had minimum curing temperature. The curing kinetics and the apparent activation energy of the resin system were studied and calculated by the differential scanning calorimetry., and the mechanical and thermal properties of the composite was analyzed. The results show that when the content of polythiol was 12% and the content of triethanolamine was 11%, the peak curing temperature of the resin system was 118°C, which was lower than the phenolic resin or phenolic/epoxy resin. Tg dropped from 212 °C of PF to 157 °C of EPF and then to 147 °C of EPF-B. The thermal decomposition temperature and residual carbon rate also showed a slight downward trend, but the mechanical properties were greatly improved. The strength and flexural modulus of EPF-B have increased from 291.4 MPa and 11.2 GPa of EPF to 440 MPa and 12.3 GPa, an increase of 49% and 27%. This research provides a theoretical basis for broadening the application range of phenolic resin and epoxy resin blending system.