SiO_2/聚四氟乙烯复合薄膜的制备及力学性能

Preparation and mechanical properties of SiO_2/polytetrafluoroethylene composite films

采用空气辅助干法共混、冷压烧结并车削成膜的方法制备了SiO_2填充量为35wt%、厚度为50μm的聚四氟乙烯(PTFE)基复合薄膜。系统研究了SiO_2颗粒粒径对SiO_2/PTFE薄膜复合材料的孔洞缺陷和力学性能等的影响,并研究了SiO_2在PTFE中的分散情况及分子间相互作用对其性能变化的影响机制。结果表明,随SiO_2粒径的逐渐增大,其在PTFE中的分散趋于均匀,同时PTFE能更好地包覆粒子,因此SiO_2/PTFE薄膜孔洞缺陷逐渐减少,力学性能逐渐增强;当SiO_2的粒径D50为12μm时,其在PTFE中的分散均匀性最佳,SiO_2/PTFE复合薄膜孔洞缺陷最少,具有较好的力学性能,断裂伸长率达19.5%,拉伸强度达9.2MPa。

The SiO2/polytetrafluoroethylene(PTFE)composite films with 35 wt% SiO2 and the thickness of 50μm were prepared by air-assisted dry blending,cold-pressing,sintering and skiving techniques.The effects of SiO2 particle size on the pinhole defects and mechanical properties for SiO2/PTFE composite films were investigated,and the influence of the dispersion of SiO2 in PTFE and the intermolecular interaction on the mechanism of its performance was also studied.The results show that with the increasing of SiO2 particle size,the dispersion throughout the PTFE matrix tends to be uniform,and PTFE can coat the particles better.The pinhole defects of the SiO2/PTFE composite films are reduced and the mechanical properties are improved.When the particle size(D50)of SiO2 is12μm,the distribution in the PTFE matrix is most uniform,the pinhole defects are least,and the PTFE/SiO2 composite film exhibits optimum mechanical properties.The elongation at break is 19.5%,and the tensile strength is9.2 MPa.