PET, a representative polyester, can be recycled through glycolysis by converting it into BHET, a monomer. However, widely used metal salt catalysts can leave residual heavy metals in the product, necessitating subsequent recrystallization and wastewater treatment. Alternative catalysts such as ionic liquids, meanwhile, require separate recovery processes because of their homogeneous nature, limiting their cost competitiveness.
 

Professor Hyeong Jun Kim is developing bead-type catalysts that retain their catalytic activity while allowing recovery by simple filtration. His approach immobilizes one ion on a polymer chain while leaving the counterion free to act as the active species. A key focus of the research is to elucidate how glycolysis activity varies with counterion identity and to improve mass transfer through control of the porous architecture, thereby enhancing both catalyst performance and lifetime. The research further aims to demonstrate a continuous depolymerization process for waste polyester fibers and glass fiber-reinforced composites, integrating polymer-to-monomer conversion, glass fiber recovery, and catalyst recovery and reuse into a single process. By enabling repeated catalyst reuse rather than consumption, this approach seeks to fundamentally improve the economics of chemical recycling.
 

This research is significant in that it provides a chemical recycling pathway for waste fibers and industrial composites that cannot be mechanically recycled and would otherwise be landfilled or incinerated. By eliminating catalyst post-treatment steps and reducing associated costs, the technology is expected to create environmental and social value as a resource recovery solution that supports carbon neutrality and the circular economy.