同向非对称双螺杆混沌混合制备导热高分子材料性能研究

Study on Property of Thermal Conductive Polymer Processed with Chaotic Mixing in Co-rotating Non-symmetric Twin-screw

以聚丙烯(PP)为高分子材料基体,选用粒径为3μm的氧化铝(Al2O3)导热填料,采用新型同向非对称双螺杆挤出机为加工设备,制备PP/Al2O3导热高分子材料,通过力学性能、熔体流动速率、热变形温度、维卡软化温度、热导率和扫描电镜的测试分析,研究混沌混合加工对导热高分子材料性能的影响。结果表明:随着Al2O3含量的增加,PP/Al2O3导热高分子材料的拉伸强度先增大后减小,冲击韧性逐渐下降,加工流动性能变差,弯曲性能和抵抗热变形能力提高,热导率逐渐增大,Al2O3含量为20%左右达到逾渗阈值,当Al2O3含量为50%时,其热导率是纯PP的1.7倍。微观形态观察表明:Al2O3含量为30%时,PP/Al2O3导热高分子材料的综合性能最好,同传统双螺杆挤出相比,同向非对称双螺杆混沌混合加工可以制备出力学性能、热性能、导热性能等更加优异的填充型导热高分子材料。

Using polypropylene（PP） as polymer matrix, alumina（Al2O3） with particle size 3 pm as thermal conductive filler, and novel co-rotating non-symmetric twin-screw extruder as processing machine, PP/Al2O3 thermal conductive polymer was prepared. Through measuring analysis of mechanical property, MFR, HDT, VST, thermal conductivity and SEM, the influence of chaotic mixing processing on the property of thermal conductive polymer was studied. The results show that： with the increasing of Al2O3 content in PP/Al2O3, tensile strength increases at initial and then decreases, impact toughness decreases gradually, processing flowability becomes poor, bending property and thermal deformation resistance improve, and thermal conductivity increases gradually. Thermal conductivity of PP/Al2O3 reaches percolation threshold value at 20% Al2O3, and is 1.7 times as that of pure PP at 50% Al2O3. Morphological structure further indicates that the comprehensive property of PP/Al2O3 thermal conductive polymer is better at 30% Al2O3. Compared with traditional twin-screw extruder, filling thermal conductive polymer with excellent mechanical property, thermal property and thermal conductive property can be processed with chaotic mixing in co-rotating non-symmetric twin-screw extruder.