Circularity in polyamide textiles: enhancing recycled polymer molar mass with carbodiimide linear coupling.
BACCARIN, Graziela Solferini; COSTA, Mateus Oliveira; GARCIA, Rodrigo Henrique dos Santos; TREBBI, Bruno; AZEVÊDO, Eduardo Ribeiro de; FERREIRA, Marco Antonio Barbosa; STAFFA, Lucas Henrique; CRUZ, Sandra Andrea.
BACCARIN, Graziela Solferini; COSTA, Mateus Oliveira; GARCIA, Rodrigo Henrique dos Santos; TREBBI, Bruno; AZEVÊDO, Eduardo Ribeiro de; FERREIRA, Marco Antonio Barbosa; STAFFA, Lucas Henrique; CRUZ, Sandra Andrea.
Abstract: Textile waste from clothing production poses growing environmental and economic challenges with global fabric disposal expected to reach 148 million tons by 2030. Polyamide 6 (PA6), commonly used in fabrics, degrades during recycling due to hydrolysis, lowering its molar mass and limiting its reuse. This study presents a method to recycle PA6 fabrics using a carbodiimide (CDI) additive, which acts as an antihydrolysis agent and chain extender, aiming for cradle-to-cradle recycling. Controlling physicochemical properties, especially molar mass, is crucial; yet, the mechanisms of molar mass recovery are not well-understood and can be affected by humidity. This work showed that CDI reduced degradation in both dry and wet PA6, increasing molar mass by 40% and 75%, respectively, as confirmed by rheological analysis. Molecular investigation through 13C NMR showed no tertiary carbon signals, and Time Domain NMR indicated a higher glass transition temperature with CDI. These findings, supported by Density Functional Theory (DFT) calculations, suggest that CDI promotes linear chain extension over branching. This approach supports closed-loop recycling of PA6 fabrics, enhancing textile circularity and minimizing environmental impact.
@article={003296018,author = {BACCARIN, Graziela Solferini; COSTA, Mateus Oliveira; GARCIA, Rodrigo Henrique dos Santos; TREBBI, Bruno; AZEVÊDO, Eduardo Ribeiro de; FERREIRA, Marco Antonio Barbosa; STAFFA, Lucas Henrique; CRUZ, Sandra Andrea.},title={Circularity in polyamide textiles: enhancing recycled polymer molar mass with carbodiimide linear coupling},journal={ACS Omega},note={v. 11, n. 11, p. 18189-18205 + supporting information},year={2026}}