结晶性二氧化碳共聚物立体复合物的制备

CO2 emission has aroused great attention in the world, and the centre of attention has switched from simple CO2 capture and landfill to its comprehensive utilization. CO2 as starting material for the synthesis of macromolecular polymer has become an important research field of polymer science. The coupling of epoxides and CO2 to produce the biodegradable polycarbonate (CO2 copolymer) has been regarded as the most promising method. Although CO2 copolymer has already possessed certain industrial development foundation, the development of this green synthesis technology was suffered from material performance as well as product type etc. The main reasons consist in the CO2 copolymer is the amorphous structure and low glass transition temperature, which make the strength sharply decrease at higher temperature. So the development of crystalline CO2 polymer and the improvement of its thermal stability were highly desirable. As the dinuclear Co(III) complexes were developed for the highly active and enantioselective copolymerization CO2 with meso-epoxides, and various isotactic CO2 copolymers with 99% ee were produced. The project was focused on the exploration of new methods for the synthesis of crystalline CO2 polymers, especially for the homo- and hetereo-stereocomplexes with the same or different chemical structures. The solid state NMR techniques and theoretical calculation study were performed for elaborating the driving force of forming the stereocomplex. We hope that this strategy can provide an avenue for the synthesis and application of various crystalline CO2 polymers.

二氧化碳问题日益受到世界各国的重视，关注焦点已经从单纯的捕集和填埋转向碳氧资源的综合利用。其中，二氧化碳作为可再生碳源参与高聚物构筑已成为高分子学科的重要研究领域。在前期研究工作带动下，二氧化碳共聚物的工业化已具备一定基础，但却受制于材料性能、品种单一等问题，发展缓慢，主要原因在于二氧化碳共聚物为非晶且玻璃化转变温度较低，导致高温强度迅速变差等，因此，探索二氧化碳共聚物如何结晶并提高热稳定性成为重要研究课题。基于申请人发展的高活性、高立体选择性的双金属催化体系，并实现多种内消旋环氧烷烃与二氧化碳的对映选择性交替共聚，获得各种全同结构的二氧化碳共聚物的基础上，本项目旨在探索使二氧化碳共聚物结晶的新途径，重点研究具有相同或者不同化学结构二氧化碳共聚物形成立体复合物而导致结晶的过程。应用固体核磁技术和量化计算等方法，研究形成立体复合物的主要驱动力，为合成各种结晶性二氧化碳共聚物及其应用提供保障。

二氧化碳问题日益受到世界各国的重视，其作为可再生碳源参与高聚物构筑已成为高分子学科的重要研究领域，但是由于二氧化碳共聚物为非晶且玻璃化转变温度较低，导致高温强度迅速变差等，很难作为一种支撑材料。本项目拟探索制备结晶性二氧化碳共聚物的新方法，通过将具有相同（或不同）化学结构，相反构型的CO2共聚物共混，让其发生有序组装的共结晶过程，可以制备具有高结晶性的同型（或异性）立体复合物。应用廉价易得的外消旋催化剂和内消旋单体，可以直接实现CO2 共聚物分子内的有序组装，制备出的聚合物在结晶性和热稳定性上都和通过手性聚合物物理共混制备的立体复合物相当。通过此项目的研究，发现50余种具有结晶性的CO2基立体复合物，极大地拓展了结晶性聚合物的种类和其在工程、医药缓释等研究领域的潜在应用范围。在此项目的资助下，发表SCI论文5篇，授权中国专利2项，其中1项专利获得商业化应用，获得教育部自然科学一等奖和辽宁省和大连市的自然科学学术成果奖。