Basic Research On The Preparation Of Three-dimensional Automobile Special-shaped Shell By Microwave Curing Of Carbon Fiber/epoxy Resin Prepre

Carbon fiber composites are widely used in commercial and military applications because of their low density,high modulus and specific strength and high temperature resistance.The curing process is a key step in determining the performance of carbon fiber composites.Microwave curing technology has gained a lot of attention for its efficiency and safety.At this stage,research on microwave curing has focused on carbon fiber composites in flat sheets.Little work has been reported on the curing process for shaped materials.This paper addresses the above-mentioned issues,taking the shaped components of automotive mirrors as the research object,comparing and analysing the microwave curing and conventional curing process,and optimising the key process parameters of the curing process with the help of kinetic analysis,forming a microwave curing process for the shaped components of automotive mirrors.In this paper,to address the above issues,we have compared and analyzed the microwave curing process with the conventional curing process,taking the shaped components of automotive mirrors as the research object.The kinetic analysis optimizes the key process parameters of the curing process and these form the microwave curing process for shaped components of automotive mirrors.The details and results of the study are as follows:（1）Using self-developed microwave curing equipment,the microwave curing and conventional curing processes of T300 carbon fiber prepreg unidirectional pavement automotive rear view mirror shaped components were studied and it was found that the glass transition temperature of the microwave cured components was 8°C higher than that of the conventional cured components and the specific heat change increased by17.2%.The energy storage modulus of microwave-cured components is an order of magnitude higher than that of the conventional cured components,reflecting the better mechanical strength of the shaped components after microwave curing.Fourier transform infrared spectroscopy showed the same product for both curing methods,but the curing degree of the microwave-cured component was 1.918 times higher than the curing degree of the conventionally cured component.Scanning electron microscopy showed that the microwave-cured samples had a homogeneous and dense structure,indicating that the microwave-cured samples with a high degree of cure did not show structural defects.（2）A study of the microwave curing process for shaped components with different curvatures was carried out.The mechanical properties,chemical structure and microscopic morphology of the samples were characterized after curing at different arcs.The modulus increases as the curvature of the member increases after microwave curing.The smaller the curvature,the more effective the heat transfer of the component.The higher the temperature at which curing is terminated,the higher the degree of cure of the resin.（3）By studying the curing behaviour of carbon fiber/epoxy prepreg,the glass transition temperature T_g,0=6.365℃for uncured prepreg and T_g,∞=108.175℃for fully cured prepreg were obtained.The activation energy（E_a）of the prepreg curing was calculated using the Kissinger and Ozawa methods in conjunction with the dynamic DSC test results and the E_aobtained were 77.57 k J/mol,80.61 k J/mol and 70.30 k J/mol respectively.The Friedman method was used to obtain the relationship between activation energy and degree of cure as E_a=78.59-46.51α.The kinetic equations most applicable to the curing of this resin system were deduced using Malek’s method,and the curing of this epoxy resin system was calculated to fit the Sestak-Berggren autocatalytic reaction model.The Kamal and Sestak-Berggren models,controlled by the diffusion equation,were introduced to accurately predict the reaction rate of the curing reaction for isothermal and non-isothermal conditions,respectively.