PTFE层压织物洗后保持耐水压的机制分析

Studies on mechanism of waterproof maintaining of PTFE laminated fabric

针对PTFE层压织物洗涤后防水性能降低的问题,采用SEM、EDS、FTIR等方法分析了PTFE薄膜的吸附行为,结果表明,PTFE吸附表面活性剂洗涤后其层压织物耐水压降低。提出用共同拉伸方法制备PTFE/PU膜,其中致密的PU膜显著降低了PTFE对洗涤剂中表面活性剂的吸附,使层压织物的耐水压得以保持。对比测试了PU、PTFE和PTFE/PU等薄膜的透湿量,结果表明,PU膜透湿过程是决定PTFE/PU膜透湿速率的关键步骤,其透湿机制基本符合溶解—扩散模型。

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.