纳米二氧化硅提高PTFE硬度的机制研究

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。

Study of Polytetrafluoroethylene Reinforced by Nano-sized SiO2

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 SiO_2 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 SiO_2 content increased to 50%.XRD(X-ray diffraction) results show the crystallinity of PTFE decreases with the increase of SiO_2 content.The fracture morphology of the composite was observed with scanning electron microscopy(SEM).The results show that SiO_2 particles in the former disperses much more homogeneously than that in the later,block the PTFE molecule movement and ordered array.Infrared ray analysis shows that Hydrogen-bonding interaction exists between nano-SiO_2 particle and PTFE molecule,which increases the hardness of composites greatly.