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A new cocured process called coresin film infusion (co‐RFI) process, which combines RFI process and prepreg/autoclave process, was introduced and four kinds of commercial carbon fiber prepreg material systems and a kind of resin film were applied to fabricate co‐RFI laminates. The compatibility between the resin film and the prepreg matrix and the application of co‐RFI process were investigated based on the resin flowability, glass transition temperature of cured resin, processing quality of laminate, and variation in resin modulus on cocured interphase region measured by nanoindentation. Furthermore, mode I (GIC), mode II (GIIC) delamination fracture toughness, and flexural strength and modulus were measured to evaluate the mechanical properties of cocured laminates with different prepreg materials. The experimental results show that thickness and fiber volume fraction of co‐RFI laminates with the four kinds of prepreg materials are similar to those of prepreg laminates and RFI laminate with acceptable differences. In addition, there are no obvious defects in co‐RFI laminates. Moreover, the reduced modulus of resin at cocured interface and glass transition temperature values of the mixed resin reflect good compatibility between prepreg matrix resin and RFI resin. The GIC, GIIC values, and flexural performances of cocured laminates lie between and even exceed those of prepreg laminates and RFI laminates, indicating no weakening effect in the cocured interface. Therefore, the co‐RFI process is believed to effectively fabricate composite with low cost and it can be applied using various prepreg systems. POLYM. COMPOS., 34:2008–2018, 2013. © 2013 Society of Plastics Engineers

A rapid curing resin system made from the diglycidyl ether of bisphenol A epoxy, modified imidazole and modified aliphatic amine was developed. The curing behaviour and following characteristic of the resin were evaluated by differential scanning calorimetric and rheological analysis, respectively. Carbon fibre-reinforced polymer composite (CFRP) laminates using this resin system were manufactured through vacuum-assisted resin transfer moulding (VARTM) under short-term curing schedule. Subsequently, studies were performed on the processing quality, mechanical properties and heat resistance of the composites. The effects of post-cure duration on the interfacial bonding and the properties of the composites were investigated. The results showed that the curing time of a CFRP laminate using the studied resin under 120 °C could be controlled within 13 min with more than 95% curing degree and few defects. There were variations of the mechanical and thermal properties of the composites with different post-cure durations. The optimum properties were obtained after a post-cure process of 60 min, and extended post-cure treatment were detrimental. The corresponding mechanism was discussed from the viewpoint of interfacial bonding between carbon fibre and epoxy matrix.

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