纳米二氧化硅提高PTFE硬度的机制研究

Study of Polytetrafluoroethylene Reinforced by Nano-sized SiO_2

采用溶剂蒸发法和固体纳米粉末混合法2种工艺制备了SiO2/PTFE复合材料。结果表明,随着SiO2含量的增加,复合材料的硬度增加,但采用溶剂蒸发法制备的复合材料具有更好的强化效果,在含量达到50%时,硬度达到最大,比固体粉末法制备的复合材料的硬度高6倍。XRD分析表明,随着SiO2含量增加,PTFE结晶度降低。SEM对其断口形貌进行观察表明,采用溶剂蒸发法制备的复合材料,纳米SiO2粒子可以较均匀分散在基体中,有效地阻碍了PT-FE分子链段的运动和规整排列。红外光谱分析表明,纳米SiO2粒子与PTFE分子之间存在着氢键作用力,因而硬度增加较大。

PTFE matrix composites were fabricated using mixing nano sized powder process and vaporizing impregnant process. Result shows that the hardness of composites increases with the increase of SiO2 content. The hardness of composites fabricated with vaporizing impregnant process is much higher than that fabricated with mixing nano sized powder process, and increases to the highest value that is about 6 times that fabricated with mixing nano sized powder process when SiO2 content increased to 50%. XRD （X-ray diffraction） results show the crystallinity of FIFE decreases with the increase of SiO2 content. The fracture morphology of the composite was observed with scanning electron microscopy（SEM）. The results show that SiO2 particles in the former disperses much more homogeneously than that in the later, block the FIFE molecule movement and ordered array. Infrared ray analysis shows that Hydrogen-bonding interaction exists between nano-SiO2 particle and FIFE molecule, which increases the hardness of composites greatly.