Deconstruction of Polymers through Olefin Metathesis.

The consumption of synthetic polymers has ballooned; so has the amount of post-consumer waste generated. The current polymer economy, however, is largely linear with most of the post-consumer waste being either landfilled or incinerated. The lack of recycling, together with the sizable carbon footprint of the polymer industry, has led to major negative environmental impacts.

Precision native polysaccharides from living polymerization of anhydrosugars.

The composition, sequence, length and type of glycosidic linkage of polysaccharides profoundly affect their biological and physical properties. However, investigation of the structure-function relationship of polysaccharides is hampered by difficulties in accessing well-defined polysaccharides in sufficient quantities. Here we report a chemical approach to precision polysaccharides with native glycosidic linkages via living cationic ring-opening polymerization of 1,6-anhydrosugars.

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers.

The growing consumption of synthetic polymers and the accumulation of polymer waste have led to a pressing need for new routes to sustainable materials. Achieving a closed-loop polymer economy via chemical recycling to monomer (CRM) is one such promising route. Our group recently reported a new CRM system based on polymers prepared by ring-opening metathesis polymerization (ROMP) of trans-cyclobutane fused cyclooctene (tCBCO) monomers.

Regulating the Thermodynamics and Thermal Properties of Depolymerizable Polycyclooctenes through Substituent Effects.

Chemical recycling to monomer (CRM) is a promising route for transitioning to a circular polymer economy. To develop new CRM systems with useful properties, it is important to understand the effects of monomer structure on polymerization/depolymerization behavior. In earlier work, this group demonstrated chemically recyclable polymers prepared by ring-opening metathesis polymerization of trans-cyclobutane fused cyclooctenes (tCBCO).

Understanding the Structure-Polymerization Thermodynamics Relationships of Fused-Ring Cyclooctenes for Developing Chemically Recyclable Polymers.

Polymers that can be chemically recycled to their constituent monomers offer a promising solution to address the challenges in plastics sustainability through a circular use of materials. The design and development of monomers for next-generation chemically recyclable polymers require an understanding of the relationships between the structure of the monomers/polymers and the thermodynamics of polymerization/depolymerization. Here we investigate the structure-polymerization thermodynamics relationships of a series of cyclooctene monomers that contain an additional ring fused at the 5,6-positions, including -cyclobutane, -cyclopentane, and -five-membered cyclic acetals.

Degradable Vinyl Random Copolymers via Photocontrolled Radical Ring-Opening Cascade Copolymerization.

Degradable vinyl polymers by radical ring-opening polymerization are promising solutions to the challenges caused by non-degradable vinyl plastics. However, achieving even distributions of labile functional groups in the backbone of degradable vinyl polymers remains challenging. Herein, we report a photocatalytic approach to degradable vinyl random copolymers via radical ring-opening cascade copolymerization (rROCCP).

Olefin metathesis-based chemically recyclable polymers enabled by fused-ring monomers.

A promising solution to address the challenges in plastics sustainability is to replace current polymers with chemically recyclable ones that can depolymerize into their constituent monomers to enable the circular use of materials. Despite some progress, few depolymerizable polymers exhibit the desirable thermal stability and strong mechanical properties of traditional polymers. Here we report a series of chemically recyclable polymers that show excellent thermal stability (decomposition temperature >370 °C) and tunable mechanical properties.