Abstract:
The SiO
2/polytetrafluoroethylene (PTFE) composite films with 35wt% SiO
2 and the thickness of 50
μm were prepared by air-assisted dry blending, cold-pressing, sintering and skiving techniques. The effects of SiO
2 particle size on the pinhole defects and mechanical properties for SiO
2/PTFE composite films were investigated, and the influence of the dispersion of SiO
2 in PTFE and the intermolecular interaction on the mechanism of its performance was also studied. The results show that with the increasing of SiO
2 particle size, the dispersion throughout the PTFE matrix tends to be uniform, and PTFE can coat the particles better. The pinhole defects of the SiO
2/PTFE composite films are reduced and the mechanical properties are improved. When the particle size (
D50) of SiO
2 is 12
μm, the distribution in the PTFE matrix is most uniform, the pinhole defects are least, and the PTFE/SiO
2 composite film exhibits optimum mechanical properties. The elongation at break is 19.5%, and the tensile strength is 9.2 MPa.