Poly(carbonate acetal) vitrimers with enhanced thermal properties and closed-loop thermal recyclability derived from waste polycarbonate-derived polyaldehyde and pentaerythritol/erythritol/D-sorbitol
Yi-Chun Chen, Kamani Sudhir K. Reddy, Ru-Jong Jeng, Ching-Hsuan Lin
{"title":"Poly(carbonate acetal) vitrimers with enhanced thermal properties and closed-loop thermal recyclability derived from waste polycarbonate-derived polyaldehyde and pentaerythritol/erythritol/D-sorbitol","authors":"Yi-Chun Chen, Kamani Sudhir K. Reddy, Ru-Jong Jeng, Ching-Hsuan Lin","doi":"10.1039/d4gc02934h","DOIUrl":null,"url":null,"abstract":"We synthesized three poly(carbonate acetal) vitrimers (PCA-P, PCA-E, PCA-S) by condensing a waste polycarbonate-derived polyaldehyde (WPC-CHO) with pentaerythritol, erythritol, and <small>D</small>-sorbitol, using 0.5–4.0 mol% <em>p</em>-toluene sulfonic acid (<em>p</em>TSA) as a catalyst. Flexible PCA films emerged at <em>p</em>TSA concentrations ≥1 mol%, indicating a critical threshold of acid for effective condensation. The glass transition temperatures (<em>T</em><small><sub>g</sub></small>) of the films remained consistent across <em>p</em>TSA concentrations but varied based on the multi-alcohol structure, with <em>T</em><small><sub>g</sub></small> values of 178 °C for both PCA-P and PCA-S, and 142 °C for PCA-E, suggesting superior performance of pentaerythritol and <small>D</small>-sorbitol over erythritol as building blocks. Among these, the PCA-S series exhibited the best performance and utilized the least expensive starting materials, achieving the highest cost-performance index. The PCAs, featuring covalent adaptable polyacetal networks, facilitated thermal reprocessing through acetal metathesis. The second reprocessed PCA-P and PCA-S maintained similar thermal and mechanical properties to their original forms, demonstrating a closed-loop recycling. These polymers showed stability in THF/H<small><sub>2</sub></small>O (4/1) with 0.1–1.0 M H<small><sub>2</sub></small>SO<small><sub>4</sub></small> at 25 °C, but can be degraded at 50 °C within 5 hours in both 0.5 M H<small><sub>2</sub></small>SO<small><sub>4</sub></small> and HCl THF/H<small><sub>2</sub></small>O (4/1) solutions. NMR analysis of the degraded PCA-P confirmed the recovery of WPC-CHO and pentaerythritol. Furthermore, PCA-based carbon-fiber-reinforced plastics (CFRPs) were prepared, and the carbon fibers were successfully recovered after acid degradation without any loss to their structural or tensile integrity.","PeriodicalId":78,"journal":{"name":"Green Chemistry","volume":null,"pages":null},"PeriodicalIF":9.3000,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Green Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1039/d4gc02934h","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
We synthesized three poly(carbonate acetal) vitrimers (PCA-P, PCA-E, PCA-S) by condensing a waste polycarbonate-derived polyaldehyde (WPC-CHO) with pentaerythritol, erythritol, and D-sorbitol, using 0.5–4.0 mol% p-toluene sulfonic acid (pTSA) as a catalyst. Flexible PCA films emerged at pTSA concentrations ≥1 mol%, indicating a critical threshold of acid for effective condensation. The glass transition temperatures (Tg) of the films remained consistent across pTSA concentrations but varied based on the multi-alcohol structure, with Tg values of 178 °C for both PCA-P and PCA-S, and 142 °C for PCA-E, suggesting superior performance of pentaerythritol and D-sorbitol over erythritol as building blocks. Among these, the PCA-S series exhibited the best performance and utilized the least expensive starting materials, achieving the highest cost-performance index. The PCAs, featuring covalent adaptable polyacetal networks, facilitated thermal reprocessing through acetal metathesis. The second reprocessed PCA-P and PCA-S maintained similar thermal and mechanical properties to their original forms, demonstrating a closed-loop recycling. These polymers showed stability in THF/H2O (4/1) with 0.1–1.0 M H2SO4 at 25 °C, but can be degraded at 50 °C within 5 hours in both 0.5 M H2SO4 and HCl THF/H2O (4/1) solutions. NMR analysis of the degraded PCA-P confirmed the recovery of WPC-CHO and pentaerythritol. Furthermore, PCA-based carbon-fiber-reinforced plastics (CFRPs) were prepared, and the carbon fibers were successfully recovered after acid degradation without any loss to their structural or tensile integrity.
期刊介绍:
Green Chemistry is a journal that provides a unique forum for the publication of innovative research on the development of alternative green and sustainable technologies. The scope of Green Chemistry is based on the definition proposed by Anastas and Warner (Green Chemistry: Theory and Practice, P T Anastas and J C Warner, Oxford University Press, Oxford, 1998), which defines green chemistry as the utilisation of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical products. Green Chemistry aims to reduce the environmental impact of the chemical enterprise by developing a technology base that is inherently non-toxic to living things and the environment. The journal welcomes submissions on all aspects of research relating to this endeavor and publishes original and significant cutting-edge research that is likely to be of wide general appeal. For a work to be published, it must present a significant advance in green chemistry, including a comparison with existing methods and a demonstration of advantages over those methods.