Preparation and Property Studies of Organic-Inorganic Hybrid Hollow Fiber Membranes and Nano-silver Composite Plate Membranes

• Main Authors: Chia-Tseng Yao, 姚家增
• Other Authors: Jui-Ming Yeh
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/85769695867047912971

博士 === 中原大學 === 化學研究所 === 97 === Abstract This dissertation divided into two parts. The preparation of polyimide nanocomposite hollow fiber includes two kinds of additive, plate clay or spherical silica, is the first part. The preparation of polyvinyl alcohol and polyacrylonitrile plate nanocomposite membrane contain silver nanoparticle is the second part. Silver nitrite converts into silver nanoparticle by using in-situ photochemical reduction and direct chemical reduction. In this research, the structure and performance of a series of organic-inorganic hybrid materials will be investigated. In the first part, casting solution contains polyimide, NMP, and nanoparticle (flat clay or spherical silica) was used to prepare asymmetric polyimide nanocomposite hollow fiber membrane. The effect of additives on the morphology, membrane formation mechanisum, mechanical properties, and pervaporation performance of the asymmetric polyimide nanocomposite hollow fiber membrane was investigated. The results revealed that the addition of nano-filler in the spinning solution and increasing the filler amount can promote the formation of macrovoids in nonocomposite hollow fiber membrane. Otherwise, the exchange rate between the solvent and nonsolvent during the membrane formation process increases resulting in an asymmetric PI hollow fiber membrane with a wider wall thickness. The material composition will affect the thermal stability, mechanical strength and the separation performance of vapor permeation of aqueous ethanol solution. The elongation at break, strength at break, and work of rupture increase with nano-filler is a unique phenomenum different than general polymer. Moreover, water contact angle increasing presents self-clearing performance. The second part, a series of nano-scale silver polymer composite films were prepared from polyvinyl alcohol silver ions chelate aqueous solution. Silver ions transfer to silver by in-situ photochemical reduction using UV-irradiation. Other way, polyacrylonitrile silver ions chelate in N,N-dimethylformamide (DMF) will change into silver by direct chemical reduction. The reduction of silver ion in nano-composite films were confirmed by UV/vis optical absorption, Fourier-transformation infrared spectroscopy (FTIR), SEM-mapping, and X-ray diffraction (XRD). The surface morphology of nano-scale silver polymer composite films were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The amount of nano-scale silver in polymer composite films will affect the thermal stability, contact angle and antibacterial activities. In this study, we found that the structural morphology of PVA-Ag+ chelate films change vastly due to the changes in loading amount. However, silver nano-particles produced by in situ reduction UV-irradiation shown particles on the surface of PVA films. The surface morphology of PVA-Ag0 and PAN-Ag0 membrane is similar. PVA-Ag+ is effective prohibite the growth of Escherichia coli and Staphylococus aureus in 0.5 wt% silver nitrite loading. PVA-Ag0 and PAN-Ag0 films are effective in prohibiting the growth of Escherichia col. Furthermore, we demonstrated that the hybrid composite films have good hydrophobic characterization owing to the presence of nano-scale silver. From DSC experimental results, the glass transition (Tg) and melting temperatures decreases with increasing AgNO3 loading owing to destroy of the crystalline.