The Manufacture And Properties Studies Of PTFE Architectural Membrane Structure Materials

As a new space structural material, the architectural membrane structure material has the advantages of light-weight and beauty, light-transmission and energy-saving, safety and durability, and so on, which has widely been used in the stadium, exhibition hall, airport hall, shopping center, entertainment center, and other large construction projects. The architectural membrane material has wide prospect of market among new industries.The architectural membrane material is a kind of flexible composite with high-strength fiber fabric as its base fabric, utilizing some certain form of finished techniques to coat resin material on the base fabric. It mainly includes PTFE and PVC membrane materials. There is later start and less research on the architectural membrane materials domestically. At present more researches have been done on the modification of PVC membrane materials for antifouling, self-cleaning, and ageing resistant performances, less of which have been done on the production of PTFE membrane materials, which restricted seriously the domestic development of architectural membrane materials and membrane structure building. Therefore, the purpose of this subject is to exploit PTFE membrane materials and study its production process as well as its mechanical properties. In this study, superfine glass fiber woven plain fabric is used as the reinforce fabric of the membrane material, utilizing dipping coating process to make the surface coated PTFE resin. Researches on the raw material, manufacture of base fabric, heat treatment of the fabrics, the process of dipping coating, manufacture of PTFE membrane materials as well as materials' mechanical properties are conducted, involving the optimization of membrane material preparation process, tests on mechanical properties and study on related factors that may influence product's performance, aiming to provide guide and instructions for industrialized production of PTFE membrane materials.Firstly, the raw materials of PTFE membrane materials, glass fiber and polytetrafluoroethy-lene resin are analyzed, such high requirements for the base fabric of PTFE membrane material as excellent mechanical properties, high smoothness and fault-free are introduced. According to the requirements mentioned above, in this study, high-quality raw materials and equipment are chosen and appropriate structure parameters and process are used to weave three kinds of fabrics as base fabrics of PTFE membrane materials.Secondly, the effect of heat treatment process on the performances of fiberglass yarn and base fabric were studies in the paper. The results have shown that with the heat treatment temperature rising and the extension of time, the infiltration agent residues gradually reduce, and the fabric cover color gradually turned white and the tensile strength of fabric gradually reduced. Taking all factors into consideration, rational temperatures and different time of heat treatment of different base fabric are set in order to make them suitable for the next process.Thirdly, different PTFE solid content baking temperature, effects of sintering temperature and time and other factors on the adhesion of membrane materials yarn are investigated. The optimal dipping-coating parameters were determined by simple-factor, orthogonal design of experiment and analysis of statistical methods. The results have shown that the factors of PTFE solid content and sintering time are major ones, and the baking temperature and sintering temperature play a second role within a certain temperature. At last, according to temperature and time of heat treatment, the optimal dipping-coating parameters and the characteristics of fabrics, the optimal parameters of preparation of PTFE membrane materials have been obtained, and three types of PTFE membrane materials were prepared for next performance test.Tensile and tear experiments of three types of PTFE membrane materials were carried out. Thereafter, the results of which have shown that all the three can meet the requirements of mechanical properties comparing with that of domestic and abroad similar products. By comparing and analyzing the testing data, we find that the mechanical properties of the membrane materials are determined mainly by the base fabrics, on which coating process and test conditions has also exerted some influences. Several factors affecting the tensile and tear strength of the membrane materials are summarized subsequently. In addition, the utilization of yarn strength, tensile anisotropy and flexibility resistance of PTFE membrane materials were also analyzed in the paper, in order to provide some guidance to improve the mechanical properties of PTFE membrane materials.Finally, we summarize some conclusions of this subject and point out some insufficiencies and some suggestions for further researches, which can give some valuable references for the design and manufacturing of PTFE membrane materials.