# Gateway to Sustainable Polymers via Catalytic ROCOP of CO2/COS Utilizing a Renewable Epoxide Monomer from Furfural Derivatives

## TL;DR

This paper presents a sustainable method to create polymers using renewable materials from biomass, with properties suitable for various applications.

## Contribution

A novel furan-based epoxide monomer is synthesized from furfural derivatives and used in catalytic ROCOP with CO2 and COS.

## Key findings

- The synthesized polymers showed thermal stability up to 150 °C and hydrolytic degradability under basic conditions.
- Recycled diol from degraded polycarbonate was successfully converted back to epoxide monomer.
- Poly(monomothiocarbonates) exhibited higher hardness and elastic modulus compared to polycarbonates.

## Abstract

In recent years,
there has been an increase in demand for a paradigm
shift from fossil fuel-based feedstock to renewable feedstock for
polymer synthesis due to the need for expanding the source of these
materials as well as enhancing their (bio)­degradability. Lignocellulosic
biomass can serve as a promising renewable feedstock that can be converted
to platform chemicals. Furfural is one of the crucial platform chemicals
that is derived from xylan-rich lignocellulosic biomass. Furfural
is an excellent molecular platform that can open a gateway to a diverse
range of furan-based epoxide monomers. Herein, we report a furan-based
epoxide monomer synthesized by using two furfural derivatives (furoyl
chloride and furoic acid). The epoxide has been screened for catalytic
ring-opening copolymerization (ROCOP) with carbon dioxide (CO2) and carbonyl sulfide (COS) employing binary catalysts comprising
Co-salen and Cr-salen complexes, respectively, in conjugation with
phosphonium salts. The polycarbonates and poly­(monothiocarbonates)
showed thermal stability up to 150 °C with T
gs of 58.6 and 49.2 °C, respectively. The aliphatic
polycarbonate exhibited hydrolytic degradability under basic conditions
to produce diol. The diol generated by the degradation of polycarbonate
was recycled back to epoxide monomer through tosylation reaction,
followed by ring-closing of the tosylated product. The mechanical
properties of the polymer sample were accessed by performing a lap
shear test and nanoindentation testing. The lap shear test revealed
that the polycarbonate sample exhibited better adhesive performance
than poly­(monothiocarbonates), while nanoindentation testing showed
poly­(monothiocarbonates) exhibited higher hardness and elastic modulus
than polycarbonates.