Study On Injection Molding Properties Of Carbon Fiber Reinforced Composites

At present,carbon fiber reinforced composites play an irreplaceable role in various fields.In the face of intensified environmental pollution,energy conservation and emission reduction are the focus of research,while thermoplastics are reinforced substrates,which are light in weight,stable in chemical properties,and easy Processing and low cost,so it is widely used in various industries.Not only can injection molding improve the production efficiency and scale of carbon fiber composite materials,but also different process parameters can be controlled during injection molding,which is helpful to study the influence of process parameters on the properties of composite materials.In this dissertation,carbon fiber powder reinforced crystalline material polypropylene(PP)and amorphous material acrylonitrile-butadiene-styrene copolymer(ABS)are studied.The carbon fiber composite material pellets were first prepared with a twin-screw extruder,and then the research test samples were prepared using a micro injection molding machine.The influence of carbon fiber powder on the mechanical properties,rheological properties and thermal properties of composite materials was studied.The influence of four process parameters(melt temperature,mold temperature,holding pressure,injection pressure)on the mechanical properties of composite materials was studied.And through the metallographic microscope analysis,the distribution of carbon fibers in the matrix with different proportions was observed to influence the mechanical properties of the composites.The main results are as follows:(1)In the mechanical property test,the addition of CF powder has a significant effect on enhancing the elastic modulus of PP/CF composite materials and enhancing the tensile strength and elastic modulus of ABS/CF composite materials,but the addition of CF powder reduces the CF enhances the elongation at break and impact strength of crystalline PP and amorphous ABS composites.(2)Among the process parameters,the injection pressure has the largest effect on the crystalline PP material,and the elastic modulus of the PP/CF composite material is increased by 8.75%when the injection pressure is 95 MPa compared to 80 MPa.Among the reinforced amorphous ABS/CF composites,the holding pressure has the greatest influence on the improvement of tensile strength,and the holding strength of 150 MPa increases the tensile strength of ABS/CF composites by 12.6%comparedto 120 MPa.(3)In the rheological performance test,the carbon fiber reinforced crystalline PP composites and amorphous ABS composites gradually increase the melt viscosity as the CF content increases.At low shear rates,temperature has the greatest effect on the fluidity of the melt;at high temperatures,shear rate has the greatest effect on the fluidity of the melt material.(4)The addition of CF increases the melting temperature of PP material and reduces the crystallinity.In the PP/CF composite,the CF powder is partially combined with the matrix,and the cross section of the microscope shows partial agglomeration.The addition of CF increases the melting temperature of the ABS/CF composite,increases the heat of fusion of the composite,and strengthens the system.Interfacial bonding between phases.