推压成型工艺对PTFE初生中空纤维力学性能的影响

Influence of Paste Extrusion Process on the Mechanical Properties of PTFE Nascent Hollow Fiber

聚四氟乙烯（PTFE）初生中空纤维是拉伸制备PTFE中空纤维膜的先驱体，其力学性能直接影响制膜工艺和产品性能。系统考察了推压成型温度、速度和压力条件对PTFE初生纤维力学性能的影响，并通过纤维表面微观结构分析，探究其力学性能变化的内在因素。结果表明，较高的推压成型温度和压力、较低的速度，有利于制备综合力学性能较优的PTFE初生中空纤维；纤维表面树脂初级粒子纤维化是影响其力学性能的内因；相比，推压成型温度和压力变化对树脂粒子纤维化影响较大。当推压成型温度、速度和压力分别控制为50～80℃，9—15mm／min和38～42MPa时，纤维综合力学性能较好。

The polytetrafiuoretyhylene （PTFE） nascent hollow fiber is the precursor for preparation of PTFE hollow fiber membrane, of which the mechanical properties have a direct effect on the film process and product performance. Factors affecting extrudates＇ mechanical properties such as extrusion temperature, extrusion rate and extrusion pressure were investigated systematically. And by surface micro-structure analysis, the internal factors of change of the mechanical properties of the fiber were explored. Results show that： PTFE nascent hollow fiber with good over-all properties benefits from the rising in extrusion temperature and pressure and the falling in extrusion rate; the fiberization of resin particles in the surface of fiber is the internal cause of the change of mechanical properties; extrusion temperature and rate affect the iberization of resin particles greatly. The fiber with good over-all properties is prepared when the extrusion temperature, rate and pressure are 50 -80 ℃, 9 -15 mm/min and 38 -42 MPa, respectively.