{"title":"Circular Cross-Linked Polyethylene Enabled by In-Chain Ketones.","authors":"Tobias O Morgen, Stefan Mecking","doi":"10.1021/acsmacrolett.4c00660","DOIUrl":null,"url":null,"abstract":"<p><p>Cross-linked polyethylenes (PEs) are widely employed, but the permanent links between the chains impede recycling. We show that via imine formation with diamines keto-functionalized polyethylenes from both free-radical (keto-low-density PE, keto-LDPE) and catalytic (keto-high-density PE, keto-HDPE) nonalternating ethylene-CO copolymerization can be cross-linked efficiently in the melt, resulting in gel fractions of the formed cross-linked PEs of up to 85% and improved tensile properties. The imine-based cross-links in the material can be hydrolyzed at 140 °C to recycle up to 97% of the initial thermoplastic keto-polyethylene. Low keto contents of ≤1.5 mol % are found ideal to retain PE-like thermal properties, achieve sufficient cross-link density, and maintain circular recyclability.</p>","PeriodicalId":18,"journal":{"name":"ACS Macro Letters","volume":null,"pages":null},"PeriodicalIF":5.1000,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Macro Letters","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acsmacrolett.4c00660","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"POLYMER SCIENCE","Score":null,"Total":0}
引用次数: 0
Abstract
Cross-linked polyethylenes (PEs) are widely employed, but the permanent links between the chains impede recycling. We show that via imine formation with diamines keto-functionalized polyethylenes from both free-radical (keto-low-density PE, keto-LDPE) and catalytic (keto-high-density PE, keto-HDPE) nonalternating ethylene-CO copolymerization can be cross-linked efficiently in the melt, resulting in gel fractions of the formed cross-linked PEs of up to 85% and improved tensile properties. The imine-based cross-links in the material can be hydrolyzed at 140 °C to recycle up to 97% of the initial thermoplastic keto-polyethylene. Low keto contents of ≤1.5 mol % are found ideal to retain PE-like thermal properties, achieve sufficient cross-link density, and maintain circular recyclability.
期刊介绍：
ACS Macro Letters publishes research in all areas of contemporary soft matter science in which macromolecules play a key role, including nanotechnology, self-assembly, supramolecular chemistry, biomaterials, energy generation and storage, and renewable/sustainable materials. Submissions to ACS Macro Letters should justify clearly the rapid disclosure of the key elements of the study. The scope of the journal includes high-impact research of broad interest in all areas of polymer science and engineering, including cross-disciplinary research that interfaces with polymer science.
With the launch of ACS Macro Letters, all Communications that were formerly published in Macromolecules and Biomacromolecules will be published as Letters in ACS Macro Letters.
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