改性CaCO_3填充聚四氟乙烯复合材料的制备和力学性能

Preparation and Mechanical Properties of Modified CaCO_3 Filled Polytetrafluoroethylene Composites

以石蜡为改性剂,分别采用干法和湿法对重质CaCO_3进行表面处理,然后采用冷压烧结工艺制备聚四氟乙烯(PTFE)/CaCO_3复合材料,并对其力学性能进行研究。利用红外光谱分析石蜡包覆改性前后的CaCO_3的结构变化,研究了2种改性方法对PTFE/CaCO_3复合材料的力学性能的影响。结果表明,2种改性方法都可以提高PTFE/CaCO_3复合材料的断裂伸长率和拉伸强度,当质量分数为30%的湿法改性CaCO_3填充PTFE时,复合材料的断裂伸长率仍能达到200%以上。另外,采用不同改性方法和改性剂比例及CaCO_3含量所制备的复合材料力学性能相差很大,其中,当CaCO_3质量分数为5%,湿法改性的改性剂石蜡质量分数为1%时,复合材料的各项力学性能达到最佳,远好于未经改性的CaCO_3填充聚四氟乙烯复合材料。

Paraffin was used to modify the heavy CaCO3 by means of surface-coating, including dry modification and wet modification methods, polytetrafluoroethylene （PTFE）/CaCO3 composites were prepared by die pressing and sintering, and the mechanical properties were studied. The structure of modified and unmodified CaCO3 was analyzed by infrared spectrum analysis characterization. The effect of two different surface modification methods on mechanical properties of PTFE/CaCO3 composites was investigated. The＇ results show that the two modification methods can lead to improvement of the elongation at break and tensile strength of PTFE/CaCO3 composites. The elongation at break of PTFE is as high as 200 % when the mass fraction of CaCO3 reaches 30 %. The mechanical properties of composites prepared by different modification methods show great differences. In addition, when the mass fraction of CaCO3 is 5 % and the paraffin modifier mass fraction is 1%, the mechanical properties of composites are the highest. It is far better than the mechanical properties of composites filled with unmodified CaCO3.