PP/石墨/Al_2O_3导热复合材料的制备及性能

Preparation and Properties of PP/Graphite/Al_2O_3 Thermal Conductive Composites

选择粒径为15μm鳞片石墨(FG)和3μm Al2O3混杂导热填料,采用新型同向非对称双螺杆挤出机,当Al2O3质量分数为20%时,改变FG的质量分数,制备PP/FG/Al2O3导热复合材料,研究混沌混合加工对导热复合材料性能的影响。结果表明,随着FG含量的增加,导热复合材料的拉伸强度和弯曲强度均呈现先增大后减小的趋势,而断裂伸长率、冲击强度逐渐减小,弯曲弹性模量逐渐增大,加工流动性能变差。当FG质量分数为40%时,导热复合材料的拉伸强度和弯曲强度有最大值,分别为32.76,46.88 MPa;抵抗热变形能力和热稳定性能逐渐提高,热导率逐渐增大。当FG质量分数为50%时,维卡软化温度提高7.2℃,负载变形温度提高38.6℃,最大分解速率温度提高13.7℃,热导率是未填充FG的6.6倍、纯PP的7.9倍。制备的导热复合材料具有优异的力学、耐热、导热性能。

Using flake graphite（FG） with particle size 15 μm and Al2O3 with particle size 3 μm as hybrid thermal conductive filler and novel co-rotating non-symmetric twin-screw extruder,PP/FG/Al2O3 thermal conductive composites were processed at keeping the filling content of 20%Al2O3 and changing the filling content of FG. The influence of chaotic mixing processing on the properties of the composites was studied. The results show that with the increasing of FG content,the tensile strength and flexural strength of the composites increase at initial and then decrease with maximum value 32.76,46.88 MPa at 40%FG,the elongation at break and impact strength decrease gradually,processing flowability becomes poor. The thermal deformation resistance and thermal stability improve gradually,and thermal conductivity increases gradually. At 50%FG,vicat softening temperature,heat distortion temperature and maximum decomposing rate temperature increase 7.2℃,38.6℃and 13.7℃respectively,and thermal conductivity is 6.6 times of unfilled FG and 7.9 times of PP. The thermal conductive composites with excellent mechanical properties,thermal property and thermal conductive property can be processed.