Preparation And Performance Research Of Long-shelf Life And Low Temperature Carbon Fiber/Epoxy Resin For Hot-melt Prepreg

The traditional high and moderate temperature curing prepreg moulding can result in high internal stress in composites, high energy consumption, and the narrow selection range in auxiliary material such as mould, which eventually led to high-cost of composite moulding.The long-shelf life and low temperature prepreg can greatly reduce high-cost.On the other hand, it can further reduce energy consumption because of the long-shelf life, thus the long-shelf life and low temperature prepreg will be a very important development direction in cutting down the cost of advanced composite.In this paper, with the combination system of the solid and liquid bisphenol A epoxy reisn for resin matrix, MNA as curing agent, BTEAC commonly used for phase transfer catalyst and cationic surfactants as accelerator, carbon fiber as strength material, the long shelf life and low temperature prepreg was prepared by the hol-melt route. The effect of the content of curing agent and accelerator on the film property, the viscosity-temperature characteristics, curing temperature and shelf life at RT was investigated by the DSC and rotational rheometer.The results show that the formula involves epoxy resin/curing agent/accelerator with mass proportion of 100/48～51/1.5～2.The epoxy resin film prepared by this system can be cured at 85℃, have excellent film forming properties and shelf life at RT for 8days.The carbon fiber/epoxy resin prepreg was prepared by the carbon fiber and epoxy resin film obtained by optimized epoxy resin formula.The effect of hot roller temperature, pressing times and line speed on the prepreg impregnation were investigated. The results show that the impregnation effect was the best, and the physical properties of prepreg is uniform and stable when the hot roller temperature was 65℃～70℃, line speed was 3m/min-4m/min, pressing times was 13times～17times. The unidirectional composites laminates were prepared by the moulding process.The mechanical properties, water absorption, hygroscopicity and fracture morphology were studied.The results show that the composites had excellent mechanical performance, such as flexural strength was 1025MPa, interlaminar shear strength was 70MPa. The composites had good interface bonding performance, low water absorption and low hygroscopicity.