| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 95 === Polyelectrolyte complexes (PECs) membranes composed of chitosan and poly(acrylic acid) (PAA) were prepared in this study. The membranes were embedded with various amounts of silica derived from sol-gel reactions under acidic condition. The membranes were characterized by Fourier transform-infrared specrometer (FT-IR), X-ray diffractometer (XRD), scanning electronic microscopy (SEM) and energy dispersive X-ray spectrometer (EDX). In addition, thermal properties of PECs embedded with different amout of silica were investigated by thermal gravimetric ananlysis (TGA). The swelling behaviors of PECs with different PAA ratios , silica contents and methanol compositions were also studied. Furthermore, proton conductivity and pervaporation performances including separation factors and permeabilities were investigated with various PAA ratios, silica contents, methanol feed compositions, temperatures, and sol-gel reaction times.
It is found that an increase of PAA ratio in PECs membranes decreased the swelling degree and improved the pervaporation performance. With 5 wt% of silica content, both separation factor and proton conductivity reached their maximum for PECs membrane contained 35 wt% PAA. Separation factors increased with increasing methanol feed compositions. Although the proton conductivities increased with increasing operation temperatures, the separation factors did not follow the same trend. It is assumed that larger networks in size were formed by increasing sol-gel reaction time. The effects of sol-gel reaction time were investigated by both pervaporation and impedance analysis.
To sum up, with proper amount and sol-gel reaction time of silica, membrane performance could be increased both in methanol separation and proton conductivity.
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