Preparation And Properties Of Broadened Carbon Fiber Reinforced Modified Polyethylene Prepreg

As an important part of advanced composite materials,CF-prepreg composite material have become more widely in the field of civilian and military markets because of specific strength,specific stiffness and facilitate design.There is growing demand for the ability to product mass hot melt prepreg material with the widely demand in the automotive industry,aerospace,etc..In order to strengthen the interface combining ability between resign and fiber,the key of technology is to solve the problem of the molten resign of high viscosity and dispersion of the fiber.In terms of spreading fiber,this paper design method of air spread yarm system and the process parameters were studied.Results show that when the cavity of spreading yarn though the hot air and the frenquency of cylinder is 550 Hz and the motor transmission ratio is 1.089,the carbon fiber of 12K and T700 can been widen from 7mm to 21(±1)mm successfully.In order to reduce the viscosity of the resin while increasing the properties of the resin,five kinds of proportion of PP were added to modify the high-density polyethylene and the linear low-density polyethylene respectively.The mixture was granulated using an extruder granulation system.DSC,rotational rheometer,torque rheometer and other test methods were used to characterize the melt rheological properties of the formulation resin,which is preferred mixed resin ratio formula,thereby enhancing the effect of prepreg infiltration.It was found that the shear viscosity of modified HDPE increased with the increase of HDPE content,and the shear viscosity,equilibrium torque and mechanical energy were the lowest when the ratio of HDPE:PP was 2:8.The shear viscosity of modified LLDPE decreases with the increase of LLDPE content,and the shear viscosity,balance torque and mechanical energy consumption of LLDPE are the lowest when the ratio of LLDPE:PP is 8:2.Four kinds of composites(HDPE:PP=2:8,4:6;LLDPE=8:2,6:4)were used to prepare prepregs for the expansion of the carbon fiber matrix resin,and the expanded carbon fiber reinforced polyethylene laminate composites were prepared by compression molding.Then the tensile and interlaminar shear properties of the composites were studied and compared.The results showed that HDPE/PP = 2:8 had the highest tensile strength and interlaminar shear strength among the four modified polyethylene formulations,followed by No.3 formulation(LLDPE:PP = 8:2).The ratio of resin formulation has little influence on the tensile properties of the composites.The main purpose of this study is to explore the feasibility of continuous unidirectional carbon fiber reinforced polyethylene composite prepreg manufacturing process for continuous carbon fiber reinforced thermoplastic prepreg composite materials to find efficient and feasible production technology.