| Summary: | 碩士 === 中原大學 === 化學工程研究所 === 85 ===
In this study, SBS-g-DMAEMA membrane was prepared by UV-induced graft polymerization using styrene-butadiene-styrene copolymer (SBS) as substrate, dimethylamino ethyl methacrylate (DMAEMA)as monomer and benzoin ethyl ether as photoinitiator. By changing the reaction conditions, such as monomer concentration, irradiation time and irradiation temperature, SBS-g-DMAEMA membranes with different degree of grafting were obtained. The permeabilities, selectivities, diffusivities and solubilities for gases of Oxygen and Nitrogen through these modified membranes were determined from the steady-state and the time-lag data method, respectively, at different temperatures. Simultaneously, thermal properties of these modified membranes were examined by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).
From the experimental results, the amount of DMAEMA grafting on the membrane increases with the increase of temperature, monomer concentration and irradiation time. The energy of activation was evaluated to be 2.388 kcal/mole. The characterization of FT/IR-ATR absorption band of the grafted copolymer is located at in 1718 cm(-1) and 2760 cm(-1). An ESCA analysis of the grafted copolymer membrane surface show the contents of the clement of the C, O, N. Furthermore, from the data of DSC curves of these modified membranes, we can know that the glass transition temperature increases with the increasing of the amount of grafting onto membrane. TGA showed that the thermal stability of these modified membranes are worse than of SBS membrane.
From the experimental results, the permeabilities and diffusivities of the membranes for gases of oxygen and nitrogen through these modified membranes were decreased with the increasing amount of the grafting and lowering the operating temperature. Furthermore, selectivities and solubilities decreases with the increasing of the amount of grafting. The value of the selectivity of O2/N2 and permeability for the 4.72 mg/cm(2) grafting of the modified membrane was 5.58 and 7.13 barrers, respectively, at 5℃. From the solubilities of the oxygen in the modified membrane, amount of monomer increasing can assist to dissolve of the oxygen and to promote the selectivity of O2/N2. From this study, the SBS-g-DMAEMA membrane have the potential of the oxygen enrichment membrane.
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