A STUDY ON THE STRUCTURE OF BIAXIALLY ORIENTED PTFE MICROPOROUS FILM AND THE MECHANISM OF WATERPROOF AND WATER VAPOR PERMEABILITY

摘要

Nowadays more and more people pay much more attention to the comfortability and functionality of the clothes. Waterproof and selective permeability are of critical importance to people under critical circumstances. But conventional fabric has no, if any, waterproof property and conventional film has no water vapor permeability. Through special process film can obtain water vapor permeability but simultaneously doesn't loss its waterproof property. Among the different processes, biaxial stretching of the PTFE film is one popular method to achieve the desired properties. In this paper, the biaxially oriented PTFE microporous film was analysed. Fig. 1 is the scanning electron micrograph of the surface of PTFE film. The spider web microporous film is formed using biaxial orientation technique. In which, lots of micro-pores are connected by micro-fibrils formed when biaxial stretching process.