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.