Chemical Recycling of Thermoplastic Polyurethane Residues from the Ceramic Sector

Recycling polymers from the ceramic sector offers a promising approach to valorize industrial waste while mitigating environmental impact. In this context, the acidolysis process has emerged as an efficient method for the depolymerization of thermoplastic polyurethane (TPU), where succinic acid is used to cleave the urethane bonds in the polymer structure, enabling the recovery of recycled products that can be used in the manufacturing of new materials. Therefore, the main objective of this work is to optimize the depolymerization of TPU by varying reaction temperature, time, and the PU-to-succinic acid ratio to maximize both conversion and the quality of the recycled products. The temperature range explored was 170–200 °C, the reaction time varied from 3 to 6 hours, and the PU-to-succinic acid ratio ranged from 15 to 60. The recovered products (RPs) were characterized using FTIR, NMR, GPC and hydroxyl number (OH number). FTIR and NMR spectra showed no significant differences among the various reaction products. In a similar manner, GPC chromatograms indicated a high similarity between the products. Finally, regarding the OH number were similar to those of conventional polyols, making them suitable to be used as a substitute for petrochemical-based polyols in the synthesis of new PU.

Future work will focus on further optimizing both the reaction conditions and selected characterization methods to achieve improved outcomes, in line with the main objective of this study. This approach promotes a circular economy, decreases reliance on fossil resources, and enhances the sustainability of the ceramic sector.