Preparation of functional separation membrane by polymerization using atmospheric pressure glow descharge plasma

常压辉光放电(APG)等离子体工艺具有设备成本低、处理大基片、可连续操作等优点。制备了APG等离子体反应器，研究了APG等离子体处理、等离子体聚合和等离子体接枝聚合技术，并用氦气对聚二甲基硅氧烷进行了表面改性，考察了膜对CO2的透过性和CH4对CO2的选择性。随着APG等离子体处理时间的增加，CO_2透过率呈单峰下降，与低压等离子体处理的情况相同。经等离子体处理后，CO_2的选择性大大提高，远远超过未经处理的聚二甲基硅氧烷膜的选择性。选择性与膜表面的结构有很好的相关性，CO_2与膜表面的亲和力被认为是由于C-OH等极性基团的存在而增加的。无论等离子体暴露在C_2H_4单体中，聚乙烯薄膜都是聚合的。采用APG等离子体接枝聚合技术，在微孔聚乙烯等基材上接枝丙烯酸，制得阳离子交换膜。该方法是APG血浆所特有的。将接枝膜应用于以乙二胺四乙酸乙二酯为载体的CO2促进传输膜，利用离子交换膜中的静电力将载体固定在膜上。获得了较高的CO_2透过率和选择性。

The atmospheric pressure glow discharge (APG) plasma process would be advantageous ad regards, the cost of apparatus, treatment of large substrates and the continuous operation. We prepared the APG plasma reactor and demonstrated plasma treatment, plasma polymerization and plasma graft polymerization techniques using APG plasma.The surface of poly (dimethysiloxane) membrane was modified by the APG plasma treatment using He, and the CO_2 permeability and the selsctivity of CO_2 over CH_4 were investigated in detail. Permeance of CO_2 decreased monotomously with the increase of the APG plasma treatment time as in the case of the low pressure plasma treatment. CO_2 selectivity was much improved by the plasma treatment, and went well beyond the value of the untreated poly (dimethylsiloxane) membrane The selectivity could be well correlated with the structure of membrane surface and the affinity between CO_2 and the membrane surface was considered to increase by the existence of the polar groups such as C-OH.Polyethylene film was prepared by the APG plasma method onto the poly (dimethylsiloxane) membrane. Irrespective of the plasma exposing to C_2H_4 monomer, polyethylene film was polymerized. Therefore, polythylene film was considered to be deposited by the plasma-initiated polymerization.The cation-exchange membrane were prepared by grafting acrylic acid coated on the substrates such as microporous polythylene by the use of APG plasma graft polymerization technique. The gtafting method was peculiar to APG plasma. The grafted membrane was applied to the facilitated transport membrane using EDAH^+ as carrier of CO_2. The carrier was immobilized by the electrostatic force in the ion exchange membranes. The high CO_2 permeance and selectivity were obtained.