Research On Impregnation Process And Mold Structure Of Long Fiber Reinforced PA66 Composites

Long fiber reinforced thermoplastic composites have been widely used in all walks of life because of their excellent performance.How to prepare the high quality composite prepregs and further enhance the performance of materials have always been the focus of the scientists.In recent years,there have been many theoretical studies on the process of melt impregnation,including fiber breakage,impregnation theory and so on.However,most of them are based on the roll mold and around the processing technology.It has limitations in practical application and does not accurately describe the effect of mold on the dipping process.The impregnation mold,as an important equipment in the melt impregnation process,determines the quality of the prepreg.Based on the existing research,the paper analyzes the root causes of fiber stress and melt pressure,establishes the universal fiber fracture model and impregnation model,explores the effects of fiber processing morphology,the structure formed by fiber and mold and process parameters on the impregnation process and determines the relationship between the influencing factors and the quality of prepreg.The influence of the structure parameters of the bending flow channel mold and the process on the fracture rate and the degree of impregnation was explored by using the Design Expert software to simulate and experiment,and simultaneously the optimal parameters under the given conditions were obtained.The calculation program is used for predicting the quality of the prepreg and selecting,designing and matching the material,mold structure,and process which is desighed with the theoretical models.The results show:increasing the radius of the fiber’s bending arc and reducing the total coating angle of the fiber and the total length of the fiber in the impregnation mold are beneficial to reduce the fiber stress and fiber fracture rate;with the wedge angle decreased and the number of wedge area increased,the capacity for building pressure of melt can be increased,and then the degree of impregnation will be improved.In order to enhance the impact property of long glass fiber reinforced PA66 composites,glycidyl methacrylate grafted ethylene octene copolymer(POE-g-GMA)and maleic anhydride grafted ethylene octene copolymer(POE-g-MAH)are choosed for comparative study as the toughening agents.The results show that with the content improved of the two toughening agents,it will be increased for the impact strength of the long glass fiber reinforced PA66 composites and the interface bonding between the resin and the fiber.Among them,the effect of POE-g-GMA is more obvious and the mechanical properties of the composites are improved effectively.