Microwave curing kinetics of carbon‐fiber‐reinforced epoxy composites by wet filament winding process

Abstract A high‐performance compound epoxy resin system suitable for wet filament winding was designed. The glass transition temperature reached 181.3°C, and the tensile strength, tensile modulus, and elongation of the resin casting body were 90.82 MPa, 3312.72 MPa, and 4.17%, respectively. In order to explore the mechanism of microwave curing, the microwave curing kinetics of the composites was studied. Based on differential scanning calorimetry, the curing degree and curing reaction rate of thermal and microwave curing composites were compared. The results showed that the curing degree and curing reaction rate of microwave curing composites were higher than that of thermal curing in the early and middle stages of curing reaction. The heat transfer mechanism model was proposed. The heat transfer of carbon fiber after absorbing wave is the reason for the above‐mentioned phenomenon. In the later stage of curing reaction, the steric hindrance effect is greater than that of heat transfer mechanism on curing degree and curing rate, so there is little difference between the two curing methods. The kinetic parameters of thermal and microwave curing were calculated by the Malek method, and the activation energies were 70.40 kJ/mol and 61.18 kJ/mol, respectively. The correlation coefficient R² between the curing degree calculated by kinetic equation of microwave curing and measured by experiment was 0.951, indicating that the kinetic equation was in good agreement with the experimental results.