A Study on Isocyanate-functionallized Graphene Oxide/PVA Nanocomposites as Proton Exchange Membranes

• Main Authors: YU-NAI SU, 蘇裕迺
• Other Authors: Chi-Wen Lin
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/d2a4ec

碩士 === 國立雲林科技大學 === 化學工程與材料工程系 === 107 === In this paper, the purpose of this study is to study the modification of polyvinyl alcohol proton exchange membrane with isocyanate functionalized graphene oxide (GO). The natural graphite was oxidized by Hummer's method to prepare graphene oxide and functionalized graphene oxide with different proportions of 4,4'-diisocyanate dicyclohexylmethane (4,4'-Methylenebis (cyclohexyl isocyanate), HDI). HDI its molecular structure at both ends with an isocyanate (-NCO) functional groups, with hydroxyl and carboxyl reaction, the formation of amide and aminocarboxylic acid, HDI functionalized GO can be divided into three cases: (1) two pieces of GO indirectly on both ends of HDI, (2) HDI at both ends connected to the same GO surface, (3) on the GO surface connected to one end, and the other end -NCO remains unreacted. In order to discuss the difference of modified grafting sites, the functional groups were analyzed by FTIR, and the change of the interlayer distance was observed by XRD. The morphological changes were observed by SEM. Finally, the number of grafts was deduced by EDS element analysis. From the results, the surface of 40 mmol HDI / 1 g GO (iGO40) with the largest number of -NCO functional groups, when the proportion rose to 60mmol HDI / 1g GO (iGO60), the surface with the number of -NCO functional groups But will drop, push the test in the high-quality ratio, will be affected by the molecular structure of the impact of three-dimensional, affecting the graft position. In the PVA / SSA / PSSA-co-MA composite membrane, iGO10, iGO20 and iGO40 were added to the surface isocyanate functional groups, and it was expected that the activation of proton conduction by the interaction between acid and alkali pairs Will be due to esterification reaction, composite film further cross-linking results in the problem of proton conduction decline. The performance of the film was evaluated by proton conductivity, methanol permeability, water content and selectivity. From the results, the interaction between acid and alkali pairs contributes to the increase of proton conduction, and because of the presence of isocyanate functional groups on the surface with hydroxyl groups (-OH) on PVA, the film can be crosslinked to further reduce the methanol infiltration , The highest selectivity was observed at PVA / SSA20 / PSSAco-MA60 / iGO40 0.5%, the proton conductivity was 23.38 mS / cm, and the methanol permeability was 3.79 × 10-7 cm2 / s.