Structural characterization and high-temperature compressive creep of PTFE-based composites filled with inorganic nanoparticles

The PTFE-based nanocomposites with various contents of inorganic nanoparticles (n-AlN and n-Si3N4) were prepared by cold compaction followed by free sintering. The results of scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction show that PTFE spherulite formed in the nanocomposites. When 2 wt% inorganic nanoparticles were added into the PTFE matrix, the crystallinity increased from 34.3% to 42.1% and 43.2%, respectively. Moreover, the interplanar distances for each crystal plane were enlarged and the grain sizes were smaller than that of pure PTFE. In addition, the mechanical and high-temperature compressive creep properties were investigated. The results indicate that the introduction of inorganic nanoparticles largely increased the high-temperature compressive creep resistance, and the maximal reduction of percentage of creep strain was up to 68%. The tensile strengths of the nanocomposites increased with increasing filler content when it was no more than 2%, and then decreased with the further increase of the filler content, whereas the elongations at break showed a reverse tendency. Copyright © 2011 John Wiley & Sons, Ltd.