CO2-binding alcohols as potential candidates for poly(vinyl chloride) upcycling

Abstract

Despite the increasing global production of poly(vinyl chloride) (PVC), its recycling remains a major challenge, primarily due to its high chlorine content and limited compatibility with conventional recycling processes. This study explores the use of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD)-based CO₂-binding alcohols (CO₂BALs) as nucleophiles for PVC functionalization, aiming to enhance its upcycling potential. The impact of solvent polarity, CO₂BAL conversion, and reaction time on the substitution-to-elimination ratio was systematically investigated. Although the degree of substitution remained below 10 wt%, a promising S_N2/E2 selectivity of 94/6 was achieved. The functionalized materials were characterized using ¹H NMR, FT-IR, SEC, and TGA, confirming the successful grafting of carbonate moieties and highlighting thermal stability trends. While CO₂BAL stabilization in polar solvents may limit reactivity, alternative approaches, such as flow chemistry, are currently under consideration to improve substitution efficiency. This work provides new insights into CO₂-based strategies for PVC modification, bridging the gap between polymer upcycling and sustainable chemistry.