Preparation And Performance On The Polyvinyl Thermal Conductive Plastics

With the rapid development of science and technology,the mobile phone radiator,heat exchanger,floor heating pipes and other fields have been used polyvinyl conductive plastic.Polyvinyl thermal conductive plastics has corrosion resistance,easy processing and forming,material high cost performance.But its thermal conductivity is not high,poor mechanical properties of restricted the application of polyethylene matrix composite.Therefore has a high heat conductivity and has good mechanical properties of composite materials research has great theory and use value.This thesis mainly with linear low density polyethylene(LLDPE)and heat-resistant polyethylene(PERT)as the matrix.Zinc oxide(ZnO),alumina(Al2O3)as thermal conductive filler.And mainly by twin-screw extruding and molding thermal conductive composite was prepared.The main contents are as follows:(1)Studied the species and dosage of thermal conductive filler for polyethylene matrix composites performance impact.The results show that when the LLDPE as matrix,the preparation of thermal conductivity of composite materials tensile strength is poor.When the PERT as matrix,preparation of composite material mechanics performance is better.(2)Studied the dosage of coupling agent for filler and polyethylene composite performance impact.The results show that when the dosage of silane coupling agent is 2%of the ZnO filler quality score,filler activation degree is very good,thermal conductivity and mechanical properties of composites is improved.When the dosage of aluminum acid ester coupling agent is 1.5%of the Al2O3 filler quality score,filler activation degree is very good,thermal conductivity and mechanical properties of composites is improved.(3)Polyethylene grafted maleic anhydride was studied as a compatibilizer on the mechanical property of polyethylene matrix material.As compatibilizer added mass fraction is 5%of matrix,the mechanical properties improved.(4)Studied the single thermal conductive filler type,amount,particle size have effects on coefficient of thermal conductivity and mechanical properties of polyethylene matrix composites.With the increase of dosage of ZnO and Al2O3,the thermal conductivity of the composite increased gradually,elongation at break and impact strength can be gradually decline.The tensile strength increased first,then when filling mass fraction is more than 30%,the tensile strength decreased.When 38μm ZnO filling mass fraction is 70%,the coefficient of thermal conductivity is 0.74 W/(mk),When 38μm Al2O3 filling mass fraction is 70%,the coefficient of thermal conductivity is 0.97 W/(mk),The larger the particle size of the filler,the mechanical properties of polyethylene matrix composites drop greater.With the increasing amount of thermally conductive filler,melt flow rate of the composite material decline,the greater the influence on the processing.When ZnO and Al2O3 filling amount was 70%,melt flow rate of the composite material is 4.3g/10 min and 2.5g/10 min.(5)To study the different processing methods on the influence of the polyethylene matrix composites.The results show that by screw extrusion granulation and injection molding,composite material performance is better and less sample defect.(6)Research mixing different proportions of filling filler have effects on coefficient of thermal conductivity and mechanical properties of the composite material.The results show that when ZnO filling mass fraction is 70%,and the ratio of 13μmZnO and 38μmZnO is 2:5,coefficient of thermal conductivity of composite materials is largest,0.801 W/(mk).When ZnO filling mass fraction is 70%,and the ratio of 13μmZnO and 38μmAl2O3 is 2:5,coefficient of thermal conductivity of composite materials is largest,1.05 W/(mk).Through the ZnO and Al2O3 mix fill preparation composite materials.Excellent mechanical properties than the single filling performance.The recipe optimization experiment are carried at last.