Studies on mechanism of waterproof maintaining of PTFE laminated fabric

The application of PTFE membrane laminated fabric is limited owing to the decrease of its waterproof property after washing.In this paper,the adsorption property of PTFE membrane was analyzed by means of SEM,EDS and FTIR.The results show that the decrease of waterproof property of PTFE is attributed to its adsorption of surfactants in detergent.Thus,a new idea,PTFE/PU co-stretching process,was put forward,and the resulted material containing the compact PU film reduced the adsorption of surfactant remarkably and maintained good waterproof property.The water vapour permeability(WVP) of casting PU,PTFE and co-stretching PTFE/PU membranes were measured,and the results reveal that the water vapour transmitting process of PU decides the the water vapour transmittance rate of PTFE/PU and the WVP of co-stretching PTFE/PU membrane accords with dissolution-diffuse mechanism.