Study On Methods For Improving Processing Properties Of Polycarbonate And Its Composites

Polycarbonate?PC?can be widely used in various fields due to its high light transmission and excellent mechanical properties,but due to its high melt viscosity and high processing temperature,polycarbonate greatly restricts the application of polycarbonate..Melt blending with polycarbonates with auxiliaries can improve the flowability one-sidedly,but due to incompatibility between the phases,phase separation may occur or the mechanical properties of the polycarbonate may be impaired.This paper draws on the experience of polycarbonate oligomers in improving the flowability of polycarbonates and has good compatibility.The polycarbonate graft copolymers prepared by graft modification reaction can not only keep good compatibility with polycarbonate and can significantly improve the processing fluidity of the polycarbonate.In this dissertation,a polycarbonate graft copolymer was prepared by using a Friedel-Crafts acylation reaction using aluminum trichloride as a catalyst and octanoyl chloride as an acylating agent.The effect of reaction conditions on the grafting rate was explored.The graft copolymers were characterized by infrared spectroscopy,nuclear magnetic resonance,differential scanning calorimetry,and thermogravimetric analysis.PC-g-8C/PC,PC-g-8C/GF/PC,and PC-g-8C/CF/PC composites with different ratios of raw materials were prepared.The thermodynamic properties,mechanical properties and tensile fracture morphology of composites were characterized and analyzed.The results showed that:the ratio of the amount of raw material was set to PC:CH₃?CH₂?₆COCl:AlCl₃=1:1.5:3.6,the reaction time was controlled at 8 hours,the reaction temperature was set at 30°C,octanoyl chloride as an acylating agent,The highest grafting rate is 40%at this time.The addition of grafts can improve the melt flow rate of PC-g-8C/PC composites.With the increase of grafting rate and the increase of grafting content,the melt flowability can be significantly improved.Among them,the grafting rate of 40%was the most significant improvement in the processing fluidity of the composite material.The shear viscosity of the composite material hardly changed with the change of the shear rate,and the composite melt showed a distinct Newtonian fluid state.The more glass fiber is added,the more obvious the mechanical properties of the ternary composite material are.The addition of grafts can well reduce the melt viscosity of the composite.When adding a mass fraction of 9%of the graft,the melt flow rate of the GF/PC composite can be increased 12.5 times.The addition of grafts greatly increased the melt flow rate of the composites,and the more grafts added,the greater the melt flow rate of the composites.When adding9%of the graft,the melt flow rate of the CF/PC composite can be increased by 9.4times.At this point the composite exhibits a Newtonian fluid state.The addition of grafts and carbon fibers will increase the mechanical properties of composites.