Preparation of Tannin/1,6-Diisocyanatohexane PU Membranes for Antibacterial and Gas Separation Applications

• Main Authors: Hao-Yuan Lin, 林浩源
• Other Authors: Shing-Yi Suen
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/50918432650900228194

碩士 === 國立中興大學 === 化學工程學系所 === 105 === Tannin is a kind of natural polyphenols substance widely found in many kinds of plants. Related research has verified that it has anti-oxidation and antibacterial effect. Previous literatures had successfully used condensed tannin as the substrate in polyurethane foam operation to create antibacterial function for polyurethane material. Furthermore, this material is ecologically friendly due to the fact it can be biodegraded by microorganisms in the soil. Therefore condensed tannin is the appropriate raw material for antibacterial effect enhancement. In this study, condensed tannin derivatives was used as the substrate to prepare natural materials as the membrane and further used in three applications: Antibacterial-E. coli water treatment, Penicillium inhibition, and gas permeation separation. During the synthesis the mole ratio was adjusted by adding 1,6-hexamethylene diisocyanate (HDI) while temperature and reaction time was also adjusted to find the optimum parameters for membrane preparation. The resulting polymer solution was characterized by FTIR, TGA and DSC instruments to identify the product’s functional groups and thermal properties to determine the success of the synthesis. Then the PU polymer was blended with different types of soft chain polymers to prepare flexible membranes that are favorable for the applications. The results show that not only higher temperatures, longer reaction time, and higher mole ratio can increase the success rate of reaction, but they also encourage the formation of more solid products. After the optimum conditions for the reaction of Cellulose acetate and Polymethylmrthacrylate were obtained, the membranes were prepared by different phase conversion method. Finally, the membranes were used in the following applications: the anti-E. coli water treatment, Penicillium inhibition zone test, and gas separation were applied to the membranes. Antibacterial method of batch is weighted the appropriate weight of the membrane and put into 37oC, 20 mL E. coli solution (2-5×105 CFU/mL),analysis of 24 hours after the growth of E. coli, tannin and HDI as a control group to compare the antibacterial effect. Finally, the membranes were used in the following applications: the anti-E. coli water treatment, Penicillium inhibition zone test, and gas separation. For antibacterial method, measured membrane amount was added into 20 mL E. coli solution (2-5×105 CFU/mL) and incubate at 37oC for 24 hours before data collection with tannin and HDI as control group to compare the antibacterial effect. The other application of Penicillium inhibition, suspension of Penicillium spores (3×105 CFU/mL) was coated on the agar supplemented culture dish, then the sample membrane was placed on the coated agar. After 3 days, inhibition zones were observed and their sizes were measured. The results of antibacterial experiments showed that the polyurethane membranes prepared by the reaction of tannin and HDI had the expected antibacterial effect, and the vapor-induced antibacterial effect was slightly better than that of dry type. For both E. coli and Penicillium, pure polyurethane membrane was more effective in antibacterial property than that of blended polymer membranes. As for gas permeation, the selectivity of CO2 /N2 and CO2/CH4 was lower than that of N2/CH4 on the gas separation; only N2 had better effect on CH4 separation.