低吸水率和低介电损耗PTFE/SiO2复合材料制备

Preparation of Low Water Absorption and Dielectric Loss PTFE/SiO2 Composites

研究了SiO2的改性以及改性SiO2对PTFE/SiO2复合材料介电和吸水性能的影响。结果证明,SiO2经改性后,PTFE/SiO2复合材料的吸水率和介电损耗明显降低,傅立叶变换红外光谱和X光电子能谱显示经偶联剂改性处理后,硅烷偶联剂包覆在SiO2表面,改善了其与树脂基体之间界面性能,进而对复合材料的各项性能产生影响。扫描电子显微镜观察,复合材料界面间结合紧密。硅烷偶联剂改性SiO2过程中加入适量的乙酸,可以使改性效果更佳,制备的PTFE/SiO2复合材料各项性能最佳,介电常数达到2.933,损耗因子降至0.0013,复合材料热压烧结后的密度达到2.116 g/cm3、吸水率降至0.035%,热膨胀系数降至36×10^-6 K^-1。

The modification of SiO2 and its influence on the dielectric and water absorption properties of PTFE/SiO2 composites were studied.The results show that the dielectric and water absorption properties of PTFE/SiO2 composites are significantly reduced after the modification of SiO2.In addition,according to the results of FTIR and EDS,SiO2 is effectively coated with silane coupling agents,which affectes the properties of the composites.The SEM of PTFE/SiO2 composites indicates that the interfacial binding force between SiO2 and PTFE is obviously increased.The performance of the composites prepared by the SiO2 treated by alcoholic solution of acetic acid are optimized.The permittivity,dielectric loss,the density after hot pressing,water absorption and coefficient of thermal expansion are reached to 2.933,0.0013,2.116 g/cm3,0.035%and 36×10^-6 K^-1,respectively.