酒石酸改性BT增强PP复合材料导热与介电性能

Tartaric Acid Modified BT to Enhance the Thermal Conductivity and Dielectric Properties of PP Composites

以酒石酸为改性剂,对钛酸钡(BT)颗粒进行表面改性,制备了聚丙烯(PP)/纳米氧化铝(Al_(2)O_(3))/改性BT系列3相复合材料。通过傅里叶红外光谱、扫描电子显微镜、介电频谱仪、导热分析仪对复合材料的红外光谱、微观形貌、介电性能、导热性能等进行分析表征。结果表明,酒石酸对BT颗粒的表面改性能有效改善BT、Al_(2)O_(3)等无机填料与PP聚合物的相容性,进而改善与聚合物基体间的界面连接,促进BT、Al_(2)O_(3)等颗粒在PP中的均匀分散,从而同时提升复合材料的导热和介电性能;当PP、BT与Al_(2)O_(3)的体积比为5∶4∶1时,改性BT/Al_(2)O_(3)/PP 3相复合材料的导热系数由0.90 W/m·K提升至1.24 W/m·K,在100 Hz时的相对介电常数由18提高到21.2,介电损耗同时由0.055降低至0.035,在25∼130℃的温度区间中,改性后的复合材料介电性能保持优异的温度稳定性,介电常数温度系数为-124×10^(-6)℃^(-1),比未改性复合材料的介电常数温度系数降低了62.8%。

The three-phase composite materials based on polypropylene(PP),nano-alumina(Al_(2)O_(3))and the bernary barium titanate(BT)modified with tartaric acid were prepared and their structure and performance were characterized by Fourier transform infrared spectrometer,scanning electron microscope,dielectric spectrometer and thermal conductivity analyzer.The results indicated that the surface modification for BT particles effectively improved the compatibility of PP with BT,Al_(2)O_(3)and other inorganic fillers,promoting the uniformity of BT,Al_(2)O_(3)and other particles dispersed in the PP matrix.As a result,the thermal conductivity and dielectric properties of the composites was improved simultaneously.The three-phase composites presented an increase in thermal conductivity from 0.90 to 1.24 at a PP\BT\Al_(2)O_(3)volume ratio of 5\4\1.Their relative dielectric constant at 100 Hz also increased from 18 to 21.2,but their dielectric loss decreased from 0.055 to 0.035.The dielectric properties of composites exhibited a good temperature stability with a dielectric constant-temperature coefficient of-124×10^(-6)℃^(-1)in the temperature range of 25~130℃,and their dielectric constant-temperature coefficient decreased by 62.8%in comparison with the unmodified composites.