The Thermodynamics of Gas Sorption in Glassy Polymers

气体混合物的分离是一个具有重大工业意义的问题。聚合物技术的最新进展导致越来越多的膜用于这些分离。不同的聚合物材料通常通过测量气体吸附等温线和扩散系数来评估给定的分离。通常，获得的吸收数据是用双模模型解释的。虽然这个模型在实践中被证明是有用的，但它在本质上很大程度上是经验性的，并没有直接将吸附特性与其他材料特性联系起来。这个项目是从热力学的角度研究玻璃聚合物中气体的吸收。建立了玻璃聚合物气体吸附热力学的理论框架。吸附热将通过实验测量并用于验证理论结果。初步结果表明，吸附、机械性能和混合热之间存在一定的关系，这可能有助于气体分离材料的筛选。将结果与双模模型进行比较，可以根据力学和热力学性质对某些双模参数进行解释。

The separation of gas mixtures is a problem of great industrial significance. Recent advances in polymeric technology have led to an increasingly greater use of membranes for these separations. Different polymeric materials are commonly evaluated for a given separation by measuring gas sorption isotherms and diffusion coefficients. Frequently, the sorption data obtained is interpreted using the dual mode model. While this model has proved useful in practice, it is largely empirical in nature and does not directly relate sorption properties to other material properties. This project is an investigation of the sorption of gases in glassy polymers from a thermodynamic point of view. A theoretical framework for the thermodynamics of gas sorption in glassy polymers will be established. Heats of sorption will be measured experimentally and used to validate the theoretical results. Preliminary results suggest a relationship between sorption, mechanical properties, and the heat of mixing which might aid in the screening of materials for gas separation. A comparison of the results to the dual mode model allows an interpretation of certain dual mode parameters in terms of mechanical and thermodynamic properties.