Study On Preparation Process Of Continuous Carbon Fiber Reinforced Thermoplastic Prepreg With Micro-Protrusion Array Aided Fiber Spreading

In order to cope with the energy crisis and global warming,lightweight has become one of the important frontier technologies for the development of the automotive industry,and it has put forward urgent needs for the development and application of new high-performance lightweight materials.Among them,Continous Carbon Fiber Reinforced Thermoplastical Polymer(CCFRTP)have attracted much attention because of their excellent mechanical properties,high temperature resistance,and corrosion resistance.However,its preparation process still faces or has problems such as high viscosity of molten resin and difficulty in impregnation of fiber bundles.At present,the production of CCFRTP prepregs in the industrially developed countries of the world,such as Germany and the United States,has achieved commercial supply,and is expensive and technically blocked in China.Although a large amount of research has been carried out in this area in China,it is still in the trial production stage of the laboratory and has not yet achieved a fundamental breakthrough.Therefore,this subject intends to carry out research around the proposal and realization of the preparation process principle of CCFRTP prepreg based on micro-protrusion array aided spreading fiber.The purpose is to clarify the theory of melt impregnation of resin-impregnated fiber bundles in the preparation process of CCFRTP prepreg,to explore the influence law and mechanism of the main process parameters on the impregnation effect of CCFRTP prepreg,to obtain the quality and performance control methods of CCFRTP prepreg.The main contents are as follows:(1)Introduce the molten fluid impregnation model of CCFRTP prepreg.Describe the permeability equation of resin flowing radially along a continuous fiber bundle.Establish a model that reflects the relationship between the depth of the resinimpregnated fiber bundle and the permeability,pressure drop,immersion time,and viscosity of the molten resin.Provide a theoretical basis for further analysis of the effect of process parameters on the impregnation effect of CCFRTP prepreg.(2)The preparation process principle of CCFRTP prepreg based on microprotrusion array aided spreading fiber.A metal die with a micro-pit array is processed by laser drilling,and a resin sheet with a micro-protrusion array is peeled off thereon.Using the pinning effect formed by the micro-protrusion array and the continuous carbon fiber bundle to realize the secondary spreading of the fiber bundle.Improve the impregnation effect of matrix resin on continuous carbon fiber bundles.(3)Based on the principle of continuous fiber cutting and embedding of molten resin matrix,the corresponding CCFRTP prepreg preparation experimental device was developed,and the prototype design of the device and the strength check of key components were completed.Combined with the function of secondary spreading fiber of the micro-protrusion array,the successful preparation of CCFRTP prepreg was achieved.Provide raw materials for the following study on the improvement method of CCFRTP prepreg impregnation.(4)The effect of the length of the resin matrix impregnation area on the embedding of fiber bundles and the impregnation effect of prepreg was studied.The results show that when the length of the resin sheet impregnation area is less than or equal to 80 mm,the continuous carbon fiber bundle can be completely embedded by the molten resin;and when the critical length is less than or equal to 60 mm,the prepared CCFRTP prepreg has an ideal impregnation effect.The shorter the resin impregnation area,the better the prepreg impregnation effect.(5)The influence law and influence mechanism of the main micro-protrusion characteristic parameters on the impregnation of CCFRTP prepreg were analyzed.The results show that using a micro-pit array metal mold with a depth-diameter ratio γ <1.00(0.8~0.9),the resin sheet with micro-protrusion array features can be peeled off to achieve the ideal impregnation and embedding of carbon fiber bundle.And under the condition of constant γ value,increasing the diameter of the micro-pits of the metalmold is conducive to ensuring the resin content required to impregnate the fiber bundle in a local area,and improving the impregnation effect of the resin matrix on the fiber bundle.(6)Through research on the optimized combination of process parameters and micro-protrusion characteristic parameters,the quality and performance control methods of CCFRTP prepregs were obtained.The thermodynamic performance test of CCFRTP prepreg samples showed that the CCFRTP prepreg samples prepared by the preferred process scheme have no significant increase in melting temperature(approximately 0.81%)compared to the resin matrix reference samples,which is beneficial to the CCFRTP prepreg heat forming;The thermal decomposition temperature is increased by approximately 10.35%,the average tensile breaking strength is increased by approximately 78.29%,and the energy absorption at break is increased by approximately 28.25%,indicating that components made with CCFRTP prepreg are expected to obtain better thermal and mechanical properties.