Microwave Curing Mechanism Of Carbon Fiber Reinforced Polymer Composites

Carbon fiber reinforced polymer composites are widely used in the aerospace field due to their excellent properties.Compared with the traditional autoclave curing,the microwave curing technology has the advantages of high temperature control sensitivity,short curing time and low energy consumption.However,the mechanism of the microwave curing of carbon fiber reinforced polymer composites is still not clear,and the microwave curing process is not mature.Combining the practical demands of Natural Science Foundation of China and the aerospace manufacturing industry,the above problems were researched in this paper.The main achievements are as follows:(1)The microwave curing kinetics of carbon fiber reinforced polymer composites was established.Based on the autocatalytic model,a microwave curing kinetic model of carbon fiber reinforced polymer composites was established,and the reaction mechanism during microwave curing process was revealed.In addition,the validity of the model was analyzed.(2)An offline anisotropic dielectric constant measurement method based on the solidification feature points of carbon fiber reinforced polymer composites was proposed.Based on the Debye theory and the microstructure of carbon fiber,the mechanism of the complex dielectric constant with the degree of cure was revealed.In addition,based on the multi-layer reflectance model,the microwave absorption model of the carbon fiber reinforced polymer composites was established.The effects of material thickness,layup direction and curing degree on the microwave absorbing properties were also studied.(3)A microwave curing process of carbon fiber reinforced polymer composites was designed.Considering the influence of the microwave curing kinetics,the absorbing properties and the curing stress during the microwave curing process,the optimized microwave curing process was designed and the calculation method of process parameters including curing temperature,curing time,heating and cooling rate,and variation frequency were suggested.(4)The mechanical properties,curing stress,curing cycle and energy consumption of carbon fiber reinforced polymer composites cured by optimized and traditional microwave curing process were experimentally verified.Compared with the traditional microwave curing process,the residual stress of the composites cured by the optimized microwave curing process is reduced by 50.8%,the curing cycle is shortened by 20.8% and the energy consumption is reduced by 36.7%.At the same time,except for the bending strength remains unchanged,other mechanical properties are increased by at least 10%.