Study on the pervaporation performanceof poly(tetrafluoroethylene) composite membranes

• Main Authors: Chung-Hao Yu, 余鐘豪
• Other Authors: Ying-Ling Liu
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/14300071164268276563

碩士 === 中原大學 === 化學工程研究所 === 95 === In this study, hydrogen plasma and ozone treatment technology were applied to modify the expended poly(tetrafluoroethylene) (e-PTFE) film surface. C–H groups were introduced to the surface of PTFE films through defluorination and hydrogenation reactions under hydrogen plasma treatment. The C–H groups then served as ozone accessible sites to form peroxide groups under ozone treatment. Grafting polymerization initiating from the peroxide groups was performed on the e-PTFE film surface with using sodium 4-styrenesulfonate (NaSS) as monomer. Further treating e-PTFE-g-PNaSS with a hydrochloride aqueous solution converted sodium styrenesulfonate groups to styrene sulfuric acid coded as e-PTFE-g-PSSA. Compared with only H2 plasma treatment e-PTFE membrane, e-PTFE-g-PSSA membranes have more hydrophilicity, and no hydrophobic recovery phenomena occurred. Chitosan/e-PTFE composite membranes were prepared from casting a γ-(glycidyloxypropyl)trimethoxysilane (GPTMS)-containing chitosan solution on poly(styrene sulfuric acid) grafted expended poly(tetrafluoroethylene) film surface. The adhesion between the chitosan skin layer and the modified PTFE substrate was pretty good to warrant the high performance of chitosan/e-PTFE composite membranes using in pervaporation dehydration processes on isopropanol aqueous solution. The chitosan/e-PTFE membrane exhibited a permeation flux of 1730 g/m2h and a separation factor of 775 at 70 ◦C on pervaporation dehydration of a 70 wt% isopropanol aqueous solution, and survived after a long-term operation test in 45 days. The membrane also show good performance in wide feed isopropanol aqueous solution concentration (40-90 wt%), the water concentration of permeate still can maintain around 99 wt%. This study also used interfacial polymerization technology to prepare polyamide/e-PTFE composite membranes on modified e-PTFE membranes surface using in pervaporation dehydration processes on isopropanol aqueous solution. Investigated the polyamide/e-PTFE composite membranes stability during pervaporation process, those composite membranes were prepared by introduced three different function groups(-SO3H、-COOH、-NH2) on e-PTFE membranes surface. The result showed that when introduced amine function group on e-PTFE membranes surface, the polyamide/e-PTFE composite membranes had best stability owing to the amine group could reacted with interfacial polymerization layer formed covalent bond.