| Abstract: | 一般而言，當碳膜孔徑小於5? 時，小分子維度氣體，如H2 (2.8 ?)、CO2 (3.3 ?)、O2 (3.46 ?)、 N2 (3.64 ?)及CH4 (3.8 ?)的分離表現將由分子篩選為主要的作用機制。因此，為能獲得次微米孔徑分佈之碳分子篩選薄膜，熱裂解高分子膜成為最被廣泛使用的製備程序。過去，本研究室曾探討：(1)高分子結構、(2)高分子膜製造程序、(3)熱裂解程式及(3)摻雜奈米材料，如奈米碳管、中孔洞分子篩等方法，以改善碳膜的孔洞結構、提升碳分子篩選薄膜的氣體滲透率及選擇率。研究結果已可超越Robeson 學者於2008 年所提出之permselectivity trade-off line。於此同時，本研究室亦發現，由碳膜與鋁基材所形成之碳/鋁複合薄膜，因兩相性質不同，將難以產生理想的結合。這是由於有機-無機材料的性質不同，在兩材料間會有界面的產生，即應力集中的地方，也就是相不連續的地方；經熱裂解後，此一應力集中的地方可能因收縮而產生相分離，進而斷裂形成裂縫，影響碳膜之氣體通透分選行為。因此，本計畫的研究主題即在探討基材的物化特性對碳分子篩選薄膜之孔洞結構及氣體分選能力的影響。計畫第一年，將以高溫燒結法自製不同孔徑分佈之鋁基材，探討鋁基材燒結溫度、升溫速率、燒結持溫時間等因子對鋁基材及碳膜孔徑分佈的影響；第二年中，將採用水熱合成法製備矽- 鋁複合基材，探討矽/鋁比、水熱溫度、水熱時間等因子對矽/鋁基材之化學結構的影響；於第三年時，將以拋光技術改變基材的表面粗糙度，並同時探討高分子鑄膜液之組成、溶劑揮發動力與基材膨脹、收縮之關係。最後將整合三年所探討之影響因子，包含：基材的孔徑分佈、基材的化學結構式、基材的表面粗糙度、鑄膜液之化學組成等參數與基材阻力之關係，基材阻力將以阻抗模式估算。
It is well known that carbon materials with a very narrow micropore distribution below 1 nm makes possible to separate gas pairs with very similar molecular dimensions via molecular sieving mechanism, such as H2, CO2, O2, N2, and CH4. In our previously study, the effects of polymer precursor, pretreatment of polymer film, and pyrolysis temperature program have been evaluated. The results indicated that the permselectivity of carbon molecular sieving (CMS) membrane fabricated in our laboratory have exceeded the 2008 Robeson’s trade-off line. However, the selective layer (carbon) cannot be bond well to the Al2O3 support due to the different properties between them. In general, After the composite polymer membrane were formed by the spin coating procedure, there exist interfacial stresses between polymer and support, which builds up and finally are relaxed by forming interfacial gap due to the shrinkage of organic phase during the carbonization process. Thus, in this project, the effect of support physic-chemical characterization on the morphology and the greenhouse gas separation performance of the CMS membrane were investigated. In the first year, several different pore size distributions of alumina supports were synthesized and used to evaluate the effect on the morphology and adhesive properties of CMS/Al2O3 composite membranes. In the second year, several different chemical structure of silica/alumina support were synthesized by hydrothermal method, and it’s preparation conditions such as Si/Al ratio, hydrothermal temperature, hydrothermal time were also investigated. In the third year, the effects of roughness of the support and the viscosity of casting solution on the interfacial adhesion were investigated in detail. Final, all the parameters, such as pore size distribution, chemical structure, roughness and viscosity of casting solution were all considered to evaluate the support resistance. The supports resistances were calculated by resistance model. |
