拉伸工艺对聚四氟乙烯结构和性能的影响

通过设置不同的拉伸参数如拉伸温度、拉伸速率与拉伸长度，采用单向拉伸的方法处理聚四氟乙烯（PTFE），以研究拉伸工艺对PTFE结构和性能的影响。结果表明，拉伸处理使材料出现微纤和孔隙，提升拉伸温度与拉伸速率，增加拉伸长度均可有效降低材料密度，增大孔隙率；随着拉伸长度的增加，材料的力学性能变化明显，拉伸强度由28.72 MPa增至46.13 MPa，断裂伸长率由145 %减至85 %；材料的压缩率由6.17 %增至16.21 %，弹性回复率由3.90 %增至6.42 %，相比拉伸处理前更适合作为密封材料使用。

Effect of Stretching Process on Structure and Properties of Polytetrafluoroethylene

A series of polytetrafluoroethylene(PTFE)drawn samples were prepared by uniaxial stretching at different stretching temperatures,rates and lengths,and the effects of stretching process on the structure and properties of the drawn samples were investigated systematically.The results indicated that the density and porosity of the drawn samples were effectively reduced by increasing the stretching temperature,rate and length,and their mechanical properties varied obviously with an increase of stretching length.The tensile strength increased from 28.72 MPa to 46.13 MPa,but the elongation at break decreased from 145%to 85%.Moreover,the compression rate of the drawn samples increased from 6.17%to 16.21%at different stretching lengths,whereas the elastic recovery rate increased from 3.90%to 6.42%,indicating that the obtained drawn samples are more suitable for use as sealing materials.