Study On The Property And Curing Behavior Of Carbon Fiber Prepreg

Prepreg is a composition of resin matrix and reinforcing body, using the resin matrix impregnating continuous fibers or fabrics under strictly controlled conditions. It is an intermediate material for producing composite materials. With the development of research and application of composites materials, different manufacturing processes and different working conditions put forward different requirements on prepregs.The curing stages directly affect the performance of the finished composite material. Differential scanning calorimetry(DSC) as a thermo-analytical instrument, can reflect the prepreg curing reaction during the heat process. In order to better determine the prepreg curing process parameters, the properties of resin and prepreg should be tested, and making evaluation of the varieties of prepreg curing process,to obtain the optimum curing paremeters.Specifications of six commercialized prepreg’s physical properties, such as areal density of prepreg, areal density of carbon fiber, and the resin content were tested. According to the basic physical properties of the prepreg, it shows the stability and uniform consistency production process of prepreg. Secondly, the volatile content and the change of tack and gel time were measured, which can be used to make a certain assessments of the storage performance of prepreg.With the above tests, a comprehensive characterization of the prepreg’s physical properties was made.Through heating and cooling stages of prepreg via DSC test, three parameters such as temperature, time and pressure can be obtained. The effects of various parameters on the curing process of prepreg were analyzed. It is found that the weight per square meter of prereg have no apparent effect on the curing temperature, however it did effect the curing time. The higher resin content of the prepreg increased the curing temperature of the resin, which shows linear relationship in the range of 20% to 40% resin content. As the carbon fiber areal density increases,the time of curing and pre-curing temperature becomes longer. While the pre-curing temperature time in a certain value varies, different kinds of resin, carbon fiber have different degrees of influence on curing time. among which the influence on YPH-77 is the most.In addition,the prepreg’s curing process pressure point, which is around 100 ℃ on YPH-25 and is around110 ℃ on YPH-77, is analyzed by the test of viscosity-temperature curve and gel time. Then three curing process programs have been finalized.By comparing the mechanical properties of the molded laminates and DSC enthalpy test under every process program, enery program can play better performance of prepreg’s properties, and a solution of determining the optimum curing process parameter can be found.