Design Tomorrow’s Polymers with Biodegradability and Chemical Recyclability

报告题目：Design Tomorrow’s Polymers with Biodegradability and Chemical Recyclability

报告人：唐小燕博士, 科罗拉多州立大学

时间：2020年01月14日15:00-16:00

地点：化学楼234会议室

报告摘要：

Plastics are the most widely used man-made substances in modern life. However, the currently unsustainable practices in the production and the disposal of plastics continue to deplete out finite natural resources and create severe worldwide environmental consequences. Tackling these existing plastic waste problems requires efforts and great cooperation by all the key players, from plastic producers to recyclers, retailers and consumers. It is argued that the development of chemically recyclable and/or biodegradable polymers from biorenewable resources offers a feasible solution to solve the end-of-life issue of plastic waste and preserve our finite natural resources. In this context, we developed a series of completely recyclable polymers based on γ-butyrolactone (GBL). Among them, the ring-opening polymerization (ROP) of biorenewable bifunctional α-methylene-γ-butyrolactone (MBL) into degradable and recyclable polyester was investigated in detail: controlling vinyl-addition/ring-opening/cross-linking polymerization pathways. Moreover, poly(hydroxyalkanoate)s (PHAs), as a class of microbially produced polyesters, have gained attraction as suitable alternatives to commodity plastics due to their comparable physical properties to polyolefins and most importantly their unique ability to biodegrade in ambient environments, including oceans. Natural PHAs are isotactic polymers containing a chiral site in each repeating unit, and their properties span a wide range depending on the length of the side aliphatic chain on the b-carbon, implying their wide applications in biomedical, pharmaceutical, and packaging industries. However, currently high production costs and low production volumes of biologically produced PHAs largely limit their applications as commodity bioplastics. In the context of creating a synthetic equivalent of naturally produced PHAs, both high isotacticity and high molecular weight are typically required for practical use. Accordingly, we recently developed a catalyzed chemical synthesis route to highly isotactic biodegradable PHAs from ROP of racemic eight-membered cyclic diolides derived from bio-sourced succinate. We also developed a diastereoselective polymerization methodology enabled by catalysts that directly polymerize mixtures of eight-membered diolide monomers with varying starting ratios of chiral racemic (rac) and achiral meso diastereomers into stereo-sequenced crystalline PHAs with isotactic and syndiotactic stereo-diblock or stereo-tapered block microstructures. The material properties can be tuned by varying the catalyst and monomer structures and the ratio of starting rac/meso diastereomers.

报告人简介：

唐小燕博士，2009年于武汉大学获得学士学位，同年保送至中国科学院大学长春应用化学研究所攻读博士学位，指导教师为李悦生研究员。博士期间，主要从事单茂金属配合物的合成、表征及催化烯烃聚合研究工作。2013年，前往首都大学东京(Tokyo Metropolitan University) Kotohiro Nomura教授课题组进行合作研究，主要研究内容为钒配合物催化的乙烯(共)聚合。2015年获得博士学位后，以博士后身份加入科罗拉多州立大学(Colorado State University) Eugene Y.-X. Chen教授课题组，2018年晋升为Research Scientist II。博士后研究期间，针对人们对塑料需求的日益增加以及随之而来的全球范围的环境污染问题，唐小燕博士致力于新型生物可降解高分子材料、可回收高分子材料以及相关催化体系的开发研究工作。