Morphology and gas permselectivity of polymer mixture system

在本研究中，为了获得聚合物混合体系的形态与气体输运性质之间的关系，本文研究了以下三种类型的聚合物共混体系。聚苯乙烯/聚碳酸酯(PS/PC)共混体系的DSC、WAXD和固体核磁共振研究结果表明，溶液浇铸法制备的PS/PC共混体系膜是不相容的，PC组分部分结晶。聚合物共混物对CO_2的吸附大于简单加和性规律的预期，这主要是由PC.2的微晶数量决定的。聚(甲基丙烯酸甲酯)/聚(苯乙烯-丙烯腈)(PMMA/SAN)共混体系研究表明，PMMA与SAN具有良好的相容性，AN含量在17.9~39.5mol%之间，含量小于30~70*，符合1H自旋扩散行为。共混膜的CO_2渗透系数和扩散系数均大于可加性规律，但溶解度系数符合可加性规律。从PMMA/SAN共混体系的介电弛豫谱可以看出，SAN的加入激活了PMMA的局部迁移率，从而促进了气体的扩散和渗透。此外，还提出AN之间的距离与PMMA/SAN共混体系的相容性有关。以聚酰亚胺/聚酰亚胺(PI/PI)共混体系为原料，在不同搅拌温度下混合，制得棒状PI/柔性PI共混膜。差示扫描量热仪(DMS)和透射电子显微镜(TEM)的结果表明，当搅拌温度较高时，共混体系变得完全相容。PI/PI共混膜的渗透系数高于可加性规律。综上所述，共混后的棒状PI和柔性PI在一定程度上改善了气体的传输性能。

In this study, to obtain the relationships between the morphologies and gas transport properties of the polymer mixture systems, the following three types of the polymer blend systems were investigated.1. polystirene/polycarbonate (PS/PC) blend systemFrom the results of DSC,WAXD,and solid-state NMR for the PS/PC blend system membranes which were prepared by solution-casting, it was confirmed that the polymer blend system is immiscible and PC component is partially crystallized. The fact that CO_2 sorption amount for the polymer blend was larger than that expected from simple additivity rule was mainly explained by the amount of the crystallite of PC.2. poly (methyl methacrylate)/poly (stirene-co-acrylonitlile) (PMMA/SAN) blend systemPMMA was found to be miscible with SAN,having an AN content from 17.9 to 39.5mol% at a level of less than 30-70*, from the ^1H spin-diffusion behavior. The CO_2 permeability and diffusion coefficients of the blend membranes were larger than those expected from the additivity rule, although the solubility coefficients follow this rule. From the dielectric relaxation spectra of PMMA/SAN blend system, it was concluded that the local mobility of PMMA was activated by blending with SAN,resulting the gas diffusion and permeability promoted some extens. Moreover, it was suggested that the distance between AN is related for the miscibility of the PMMA/SAN blend system.3. polyimide/polyimide (PI/PI) blend systemRod-like PI/flexible PI blend membranes were obtained by mixing the corresponding precursors at the various stirring temperatures. From the results of DMS and TEM,it was found that the blend systems become completely miscible when the stirring temperatures is high. The permeability coefficient of PI/PI blend membrane was higher than that expected from the additivity rule. In conclusion, the blending rod-like PI and flexible PI promotes the gas transport properties some extents.