Impregnation Mechanism And Craft Optimization Of T700/PEEK Prepreg Processing

High performance thermoplastic composites have broad prospects in the field of aviation and aerospace.However,as the raw materials of composite products,thermoplastic prepreg processing technology is difficult and costly,which is one of the important factors limiting the development of high performance thermoplastic composites.In this paper,T700 carbon fiber and PEEK powder was chose as raw material to produce prepreg on the thermoplastic preparation test platform which is established based on slurry method,resin content control technology,resin impregnation mechanism and impregnation parameters optimization was studied in detail,and the continuous preparation of prepreg quality which was continuous prepared was evaluated,basic mechanical properties of T700/PEEK prepreg and its composite laminates which were molded were tested.The six parts of the process of preparing thermoplastic prepreg by slurry method were determined:yarn releasement,spread and dipping,dispersant removing,impregnation,rolling and after impregnation,and wrap-up.The three problems of the process flow were solved:alcohol was selected as the dispersant of PEEK powder,the ultrasonic assist spread and dipping process was applied and the impregnation process was divided into two stages.Limitation of carbon fiber tow dipping process assisted by mechanical stirring was founded and a better solution was sought,the slurry circulation and its concentration online monitoring system was established,the effects of resin content on the yarn Influenced by various process parameters were studied,the results showed that the prepreg resin content will increase with the effective dipping distance extend and ultrasonic power increases,and positively linear correlated with the slurry concentration.Dipping process parameters to get prepreg with 35±2.5%resin content are:effective dipping distance 20cm,ultrasonic power 360W,the slurry concentration range of 39.3g/L~43.7g/L,and craft stability was verified by continuous experiment.A lot of experiments were carried out to study the influence of different technological parameters on the porosity and size of prepreg yarn,and the best impregnation parameters were obtained.:traction rate 15~20mm/s,pre impregnation temperature of 360~370?,tension within the maximum value of 7N,rolling temperature of 330?,roller gap 0.1mm.Continuous prepreg preparation experiment was carried out,and the quality of prepreg was evaluated respectively from the surface quality,internal impregnation effect,three dimensional stability,the results showed that the prepreg surface is smooth and shiny,but the surface morphology reveal that fiber parallelism is not ideal,and a few traces of incomplete impregnation were find out;The thickness is stable at 0.21mm,and the width is about 6mm,in a shorter size range,the stability is good,but the fluctuation is larger in a longer size range.The T700/PEEK prepreg and the prepreg molded T700/PEEK composite mechanical properties are:multifilament tensile strength 1.45GPa,tensile strength of 1.71MPa,the interlaminar shear strength 66.89MPa and impact strength145.78kJ/m~2.