Preparation and characterization of poly(vinyl alcohol) membrane containing nano-grade titanium dioxide

• Main Authors: Jian-Liang Tu, 凃建良
• Other Authors: J. M. Yang
• Format: Others
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/61097911344864423948

碩士 === 長庚大學 === 化工與材料工程研究所 === 96 === The purpose of this study was to develop alkaline organic-inorganic composite electrolyte membranes, the poly (vinyl alcohol) polymer as the major material via modification with itaconic acid monomer containing carboxyl group on main chain by ultraviolet radiation to get PVA/ Poly(Itaconic acid) polymer was obtained because of its good film-fabrication ability. Then further addition of nano-grade titanium dioxide powders to polymer matrix were prepared PVA/Poly(Itaconic acid)/TiO2 organic-inorganic composite electrolyte membranes. And the composite electrolyte membranes immersed in a 40 wt.% KOH solution were examined, including composition structure, thermal properties, swelling ratio, and analysis of electrical properties, etc. It was also discussing the application feasibility in fuel cell system. Analysis of composition structure indicated that the degree of the crystallinity of PVA/Poly(Itaconic acid)/TiO2 membrane became declined, it proved that destroy the crystallinity of PVA by modified of ultraviolet radiation and also changed nano-grade titanium dioxide powders. By the thermal analysis result, the thermal degradation temperature of the composite membranes was enhanced by a modified of ultraviolet radiation and adding titanium dioxide powders, it proved the thermal stability of materials was improved. But it was found that the melt point of the composite membranes shifted to low temperature and the value of heat enthalpy was decreased. Those results indicated the crystallinity became dropped. For the swelling ratio test, the swelling ratio of the composite membranes was increased with increasing time and reached equilibrium. The immerse rate and swelling ratio of the composite membrane was increased by modified of ultraviolet radiation. But the immerse rate and swelling ratio of the composite membranes was reduced with increasing titanium dioxide content. According to the results of electrical property, the ionic conductivity of the composite membranes was increased with increasing temperature and got a lower activation energy, the electrochemical stability window were about 1.5 V.