Research on Determining Suitable Curing Parameters for Epoxy/PET Composites Based on Molecular Dynamics and Finite Element Methods

Abstract

The epoxy curing temperature and curing time are the main factors affecting the physical and chemical properties of cured structures, and determining suitable curing parameters for epoxy composites remains a challenging task. In this work, the curing temperature suitable for an epoxy composite system with reinforcing fibers was obtained based on the curing kinetics. A method for obtaining the suitable curing time based on the curing internal stress, which combines curing kinetics, molecular dynamics and numerical simulation, was proposed. The rationality of the optimized curing process was verified through comparisons of surface functional groups and mechanical and electrical properties. Compared with those obtained with the manufacturer-recommended curing process, the glass transition temperature (T g ) and mechanical, electrical and other properties of the optimized samples improved to varying degrees. The higher temperature in the postcuring stage of the manufacturer-recommended curing process caused the ether bonds (C−O−C) of the epoxy resin to break, resulting in destruction of the cross-linked network and reduction of the mechanical and electrical properties of the composite material. The curing process proposed in this paper not only improves the mechanical and electrical properties of the material but also significantly reduces the curing time. This method provides valuable insight for optimizing the curing process of other epoxy composite structures.