In‐plane and in‐depth frontal polymerization behaviors of continuous fiber‐reinforced epoxy composites

Frontal polymerization (FP) is a self‐sustaining reaction that relies on polymerization exothermicity and heat transfer. This study explores the in‐plane and in‐depth FP mechanisms of continuous fiber‐reinforced epoxy composites. First, the effects of initiator and diluent concentrations on the FP behaviors of neat epoxy resins were examined. It was found that the frontal velocity and frontal temperature of the neat resins increase with an increase of either the initiator concentration or the diluent content, depending on the polymerization enthalpy and curing kinetics. Then, the FP behaviors of continuous carbon fiber and glass fiber‐reinforced epoxy woven composites were investigated. The results showed that the in‐plane FP behavior of the composites was primarily controlled by the thermal conductivity and specific heat capacity of the continuous fibers, whereas the in‐depth FP behavior mainly depended on the pores of the woven fabrics. Highlights Frontal velocity and temperature of neat resins are controlled by the polymerization enthalpy and curing kinetics. The in‐plane FP behavior of continuous fiber reinforced composites is dependent on the thermal conductivity and specific heat capacity of the fibers. The in‐depth FP behavior of composite is determined by both the thermal conductivity of fibers and the pores of fabrics. FP behaviors and mechanism of neat resins and fiber reinforced composites.