Organocatalytic depolymerization and upcycling of waste plastic as a facile route to materials discovery

Abstract

The significant gains in the last century in the design of new polymer-forming reactions and catalysis led to macromolecules with distinctive structure-property relationships affording a vast and diverse array of applications. These materials were designed for performance, as inexpensive alternatives with long lifetimes and ease of disposal, but not for recovery and recycling. The indiscriminate disposal of these polymers together with the overwhelming volumes of polymers that end up in landfills has created an unintended environmental crisis. As it stands now, only about 10% of plastics are recycled and most is mechanical recycling, while the remaining plastics are lost to the economy (billions of dollars) after a single use. To this end, chemical recycling offers an attractive alternative to disposal or mechanical recycling as it offers plastic-to-plastic recycling as well as upcycling opportunities. We have developed a platform of active catalysts for chemical recycling of poly(ethylene terephthalate) (PET) and polycarbonates (PC) as well as the aminolysis of PET as a strategy for generating new classes of monomers and subsequent high value polymers. Functional monomers with applications ranging from urethanes, resins for additive manufacturing, high performance engineering thermoplastics to therapeutics have been explored. With this new feedstock in mind, the discovery, development and deployment of new materials provides new business opportunities as well as to drive advances in high value applications ranging from microelectronics to medicine. Since most of the efficient polymer-forming reactions have been exploited, polymer science continues to be perceived as a mature field. As advances in computational chemistry and AI continue, its influence on materials development on multiple length scales, the creation and understanding of new polymer-forming reactions, catalysis and the modeling of supramolecular assemblies is becoming more pervasive. This talk will focus on the upcycling of waste plastic to high value materials with an emphasis on therapeutics.