聚丙烯/鳞片石墨导热复合材料的制备及性能

Preparation and Properties of Polypropylene/Flake Graphite Thermal Conductive Composites

以聚丙烯(PP)为基体,鳞片石墨(FG)为填料,通过添加偶联剂、开炼机混炼、模压成型的方法,制备了具有较高热导率和优良力学性能的PP/FG导热复合材料。考察了硅烷偶联剂的品种及用量、FG的粒径及含量对复合材料热导率和力学性能的影响。结果显示,使用偶联剂处理的FG对复合材料的力学性能具有一定的增强作用,但是材料的热导率降低;当KH 550添加量为FG含量的1%时,材料的力学性能最好;随着FG粒径的增大,材料的热导率明显提高,力学性能相应下降,粒径为17μm的FG与148μm的FG制备的复合材料相比,热导率提高了52.3%,拉伸强度和弯曲强度分别由34.4 MPa和51.5 MPa下降到25.1 MPa和43.0 MPa;随着FG含量的增加,材料的热导率增大,当17μm的FG含量为70%时,材料的热导率是纯PP的22.1倍,拉伸弹性模量和弯曲弹性模量也随之增大,断裂拉伸应变和断裂弯曲应变减小,拉伸强度和弯曲强度先减小后增大,并且在FG含量为20%时降到最低。

Polypropylene(PP)/flake graphite(FG)thermal conductivity composites with high thermal conductivity and excel-lent mechanical properties were prepared by adding coupling agent,mixing and molding with PP as matrix and FG as filler.Effects of the type and amount of silane coupling agent,particle size and content of FG on thermal conductivity and mechanical properties of the composites were investigated.The results show that FG treated with coupling agent enhanced the mechanical properties of the composites,while the thermal conductivity of the composite decreased.The composites show the best mechanical properties under KH 550 amount of 1%.With the increase of FG particle size,the thermal conductivity of the material show increased obviously and the mechanical properties decreased correspondingly.Comparing with the composites prepared by FG with particle size of 17μm and 148μm,the thermal conductivity of the material increased by 52.3%,the tensile strength and bending strength decreased from 34.4 MPa and 51.5 MPa to 25.1 MPa and 43.0 MPa,respectively.The thermal conductivity of the material increased with the increase of FG content.When FG content of 17μm is 70%,the thermal conductivity of the material is 22.1 times that of pure PP,the tensile modulus and bending modulus also increased.While the tensile strain at break and bending strain at break decreased.The tensile strength and bending strength decreased first and then increased,and decreased to a minimum when FG content is 20%.