扫描电镜用于PTFE拉伸微孔膜的形态结构研究--研制中PTFE拉伸微孔膜的SEM鉴定

运用扫描电镜(SEM)图像研究了聚四氟乙烯(PTFE)粉料经过推挤、辊压和拉伸得到的微孔膜的形态结构,观察到膜是由网状纤维及由它所连接的结点所组成.单相和双向拉伸显著影响到膜结构的改变,而未经热处理的拉伸膜的丝状纤维在放置中收缩改变了膜的微孔形态结构,但在孔径测定中没有显著变化.认为纤维丝是PTFE粉料在推挤和辊压中形成的结点在拉伸中伸展引出的并产生孔隙,而由于从SEM仅能观察到1 nm深度的膜表面层,厚度达数十微米多孔膜的孔径分布应是很错杂的.

SEM Study on the Morphological Structure of PTFE Stretching Porous Membranes-SEM Identification for PTFE Stretching Porous Membranes in Preparation

The morphological structures shown in scanning electron microscope (SEM) images were investigated for polytetrafluoro ethylene (PTFE) porous membranes prepared from PTFE fine powder by mechanical processes, including extrusion, rolling and stretching. Fiber net-like structures with fiber-connected nodes could be observed in membranes. The morphology of membranes was significantly changed by stretching with unixial and biaxial and also by the fiber shrinkage if the stretched membrane was not treated under high temperatures. It is proposed that nodes are formed by PTFE particles in extrusion and rolling and then bunches of fibers were pulled out of particles in stretching to make porous formed. Since the SEM image shown for membrane surface is just 1 nm in depth, the porous distribution in 10μm-thick membranes should be very complicated.