Sustainable Polymerization Catalysis for Advanced Biorenewable Polymeric Materials

项目概述：聚合催化是将积木化学品转化为聚合物的最有效、最经济的合成技术，聚合物是现代生活和全球经济几乎所有方面必不可少的材料。目前用于合成聚合物的大多数聚合工艺使用的主要是耗竭的石油基原料，以及稀有、昂贵或有毒的金属催化剂和/或环境污染过程，因此是不可持续的。该项目的中心目标是开发可持续聚合催化剂，通过设计富含地球的、环境友好的金属和无毒有机催化剂以及高效的聚合系统，获得先进的、新型的生物可再生和可生物降解的聚乳酸(PLA)材料。首先，基于自然存在或合成修饰的金鸡纳生物碱的双功能手性有机催化剂，用于外消旋丙交酯的动力学拆分聚合或对映体选择性聚合，将同时生成手性聚(L-LA)和光学拆分的非天然(昂贵)D-LA，或高结晶性的聚(L-LA)/聚(D-LA)立体配合物。其次，利用生物良性金属催化剂和设计链转移剂开发高效的永生聚合体系，将以高效、催化的方式获得新型的功能和拓扑结构的聚乳酸材料。第三，具有特定功能的分子工程富含地球的金属络合物将促进丙交酯的立体选择性聚合，从而产生高度立体规则、高性能的PLAs。广泛影响：这项研究的更广泛影响包括：(A)在化学催化和合成、聚合物化学和聚合机理以及生物材料和可持续性方面的发现和理解；(B)社会和环境，因为这项工作是可持续催化可再生聚合物，对现代生活和全球经济必不可少的材料；(C)国际合作，使科学家能够拥有共同解决复杂问题所需的互补专业知识和设施；以及(D)培养具有在全球可持续发展工作场所取得成功所需技能的研究生和博士后研究人员。

Project Overview: Polymerization catalysis is the most efficient, economical synthesis technique to convert building block chemicals into polymers, materials essential to virtually all aspects of modern life and the global economy. Most current polymerization processes employed for the synthesis of synthetic polymers utilize predominantly depleting petroleum-based feedstocks as well as rare, expensive, or toxic metal catalysts and/or enviromentally polluting processes, therefore, are unsustainable. The Central Objective of this IUPAC (US-China-Germany) Team project is to develop sustainable polymerization catalysis, through designing earth-abundant, environmentally benign metal and non-toxic organic catalysts as well as highly efficient polymerization systems, to access advanced, novel biorenewable and biodegradable polylactide (PLA) materials.Intellectual Merit: The intellectual merit of the proposed research is threefold. First, the proposed bifunctional chiral organocatalysts, based on naturally occurring or synthetically modified cinchona alkaloids, for kinetic resolution polymerization or enantioselective polymerization of racemic lactide will simultaneously produce chiral poly(L-LA) and optically resolved unnatural (expensive) D-LA, or highly crystalline poly(L-LA)/poly(D-LA) stereocomplex. Second, the development highly efficient immortal polymerization systems enabled by bio-benign metal catalysts and designer chain transfer agents will achieve novel functional and topological PLA materials in a highly efficient, catalytic fashion. Third, molecularly engineered earth-abundant metal complexes with specific functions will promote stereoselective polymerization of lactide leading to highly stereoregular, high-performance PLAs.Broader Impacts:The broader impacts of this research include: (a) discovery and understanding in chemical catalysis and synthesis, polymer chemistry and polymerization mechanism, as well as biomaterials and sustainability; (b) society and environment, as this work is in sustainable catalysis for renewable polymers, materials essential to modern life and the global economy; (c) international collaboration that enables scientists with complementary expertise and facilities required to solve complex problems together; and (d) education of graduate students and postdoctoral researchers with the needed skills to thrive in the global sustainability workplace.