New microporous polymers for carbon dioxide selective membranes

能源安全和气候变化是全球关注的紧迫问题。在这种情况下，需要高性能的二氧化碳选择性气体分离膜来净化沼气、天然气和有效的碳捕获技术。使用聚合物膜系统去除二氧化碳提供了优于替代工艺的优点，最显著的是能量效率，因为膜在其操作中不需要热再生、相变或主动移动部件。对于任何气体分离膜，期望的是对期望的气体组分具有良好的选择性并结合高渗透性（即通量），以最小化所需的系统尺寸。不幸的是，目前的高渗透性聚合物具有不足的选择性，相反，高选择性聚合物具有低渗透性。因此，提高高渗透性聚合物（如本征微孔聚合物（PIM））的选择性是化学工程中的一个重要挑战。我们提出了一个综合的，多技能和多国的研究计划，将结合联合收割机分子建模，聚合物包装，聚合物合成，气体吸附和气体渗透性研究的计算模拟，以开发聚合物作为高二氧化碳选择性膜。PIM将通过将苯并咪唑和吡咯酮杂环单元直接掺入聚合物链中来制备。计算表明，这些杂环单元对二氧化碳具有高亲和力。所提出的聚合物设计符合PIM的概念，PIM要求聚合物链既刚性又扭曲，以阻碍固态中的空间有效包装。结合使用分子建模和聚合物填充模拟来了解气体渗透性，并最终预测PIM作为膜材料的性能，将使进一步优化聚合物的设计成为可能。实现拟议的研究方案的目标将是重要的第一步，以提供在沼气和天然气净化、碳捕获和几个利基应用中具有真实的效用的二氧化碳选择性膜。

Energy security and climate change are pressing global concerns. In this context, high performance carbon dioxide selective gas separation membranes are required for purification of biogas, natural gas and efficient carbon capture technology. Carbon dioxide removal using a polymer membrane system offers advantages over alternative processes, most notably energy efficiency, as membranes do not require thermal regeneration, a phase change or active moving parts in their operation. For any gas separation membrane, it is desirable to have good selectivity for the desired gas component combined with high permeability (i.e. flux), to minimise the required size of the system. Unfortunately, current highly permeable polymers possess insufficient selectivity and conversely highly selective polymers possess low permeability. Therefore, the goal of enhancing the selectivity of highly permeable polymers, such as Polymers of Intrinsic Microporosity (PIMs), is an important challenge in chemical engineering. We propose an integrated, multi-skilled and multi-national programme of research that will combine molecular modelling, computational simulation of polymer packing, polymer synthesis, gas adsorption and gas permeability studies to develop polymers for use as highly carbon dioxide-selective membranes. PIMs will be prepared with the direct incorporation of benzimidazole and pyrrolone heterocyclic units into the polymer chains. Calculations show that these heterocyclic units possess a high affinity for carbon dioxide. The proposed polymer design conforms to the concept of PIMs, which requires polymers chains that are both rigid and contorted to frustrate space-efficient packing in the solid state. The combined use of molecular modelling and polymer packing simulations to understand gas permeability and, ultimately, predict performance of PIMs as membrane materials will enable the design of further optimised polymers. Achieving the objective of the proposed research programme would be an important first step towards providing carbon dioxide selective membranes of real utility in biogas and natural gas purification, carbon capture and for several niche applications.