Post-polymerization Modification of Polystyrene through Mn-Catalyzed Phosphorylation of Aromatic C(sp2)-H Bonds

Published: May 16, 2024

The high flammability and lack of charrability polystyrene (PS) pose significant limitations on its broader applications. Therefore, there is an urgent need for a straightforward efficient method the synthesis flame-retardant PS, which still poses considerable challenge. In this study, we present approach to enhance properties PS through direct phosphorylating aromatic C(sp2)-H bonds using commercially available inexpensive manganese catalyst. A range phosphonates served as reactive substrates enable tunable degree polymer functionalization. corresponding phosphorylated specimens were determined by means 1H NMR, 31P FTIR spectroscopy GPC. Microscale combustion calorimetry (MCC) tests indicate that protocol indeed enhances performance PS. Moreover, other advantages associated with incorporation phosphonate group have been observed, including improved thermal resistance wettability. This cost-effective strategy Mn-catalyzed C-H can also be utilized directly obtain modification waste foamed styrene acrylonitrile copolymer, providing new purpose recycling upgrading plastics.

Language: Английский

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Hydroesterification of Polycyclooctene to Access Linear Ethylene Ethyl Acrylate Copolymers as a Step Toward Polyolefin Functionalization

Macromolecules, Journal Year: 2024, Volume and Issue: 57(22), P. 10767 - 10777

Published: Nov. 15, 2024

To advance a strategy of polymer-to-polymer upcycling waste polyolefin by dehydrogenation then functionalization, we report successful hydroesterification polycyclooctene (PCOE), an analogue for partially unsaturated polyethylene. Here, convert PCOE to linear analog poly(ethylene-co-ethyl acrylate) (EEA) across range ethyl acrylate incorporations (0 18 mol % ethylene units). The ester incorporation was well controlled reaction time, and the remaining C═C bonds were subsequently hydrogenated. bulky groups did not incorporate into orthorhombic PE crystals, decreasing crystallinity, crystallite size, melting temperature with increasing functionalization. Additionally, tuned dynamic mechanical properties, both glass transition storage modulus in rubbery regime greater EEA analogs reported here achieve remarkable extensibility (strain > 4000%) high toughness, comparable commercial random branched EEA. Ultimately, demonstrate conversion dehydrogenated favorable properties.

Language: Английский

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CoSalen-Catalyzed Radical Hydrofunctionalization of Unactivated Internal Olefins at Low Catalyst Loading: Method Development, Regioselectivity, and Applications in Post-Polymerization Modification

Published: Feb. 29, 2024

The past two decades witnessed the rapid development of CoSalen-catalyzed hydrofunctionalization reactions, mostly on terminal and conjugation-activated olefins. However, use 1,2-dialkylsubstituted alkenes continues to pose challenges. In this study, we revisit substrate class in context Carreira-type reactions introduce a simple yet effective modification (over 250-fold-increase TON). Near-quantitative yields can be achieved at low catalyst loading, typically 0.05 mol%. key lies inhibiting degradation Salen backbone using molecular sieves. This new protocol facilitates study MHAT regioselectivity type alkenes. We found that allylic electron-negative groups hyperconjugation have profound effects, yielding regioisomeric ratios ranging from 6.5:1 < 1:20. high TON, mild conditions, versatility method further enable its application post-polymerization several olefin-rich, commodity-relevant polymers.

Language: Английский

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In-situ noncovalent interaction of ammonium ion enabled C–H bond functionalization of polyethylene glycols

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: May 24, 2024

Abstract The noncovalent interactions of ammonium ion with multidentate oxygen-based host has never been reported as a reacting center in catalytic reactions. In this work, we report reactivity enhancement process enabled by non-covalent interaction ion, achieving the C–H functionalization polyethylene glycols acrylates utilizing photoinduced co-catalysis iridium and quinuclidine. A broad scope alkenes can be tolerated without observing significant degradation. Moreover, cyano-free condition respectively allows incorporation bioactive molecules PEGylation dithiothreitol-treated bovine serum albumin, showing great potentials drug delivery protein modification. DFT calculations disclose that formed α -carbon radical adjacent to oxygen-atom is reduced directly before acrylate addition. And preliminary mechanistic experiments reveal PEG chain quinuclidinium species plays unique role site facilitating proton transfer ultimately enabling transformation efficiently.

Language: Английский

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Photocatalysis as a tool for upcycling of polymers

Trends in Chemistry, Journal Year: 2024, Volume and Issue: 6(7), P. 392 - 405

Published: June 15, 2024

Language: Английский

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Aliphatic C–H Insertion Strategies Enhancing Interactions among Waste Rubbers for Recycling

ACS Applied Polymer Materials, Journal Year: 2024, Volume and Issue: 6(15), P. 9306 - 9311

Published: July 31, 2024

The recycling of waste rubber (WR) is beneficial to the sustainable development industries. However, interactions among WR are weak, limiting WR. In this work, our group designed bis-diazo compounds promote for through aliphatic C–H insertion strategies. Specifically, upon hot pressing, produce bis-carbenes which react with on surface by insertions, and then we obtain recycled materials. As a result, stress–strain curves show that strength increases steadily increase compound loading, has reached level butadiene styrene rubbers. Moreover, introduced disulfide bonds endow reprocessability. Stress–relaxation experiments at different temperatures have unique vitrimer viscoelastic properties. feasibility enhance insertions opens opportunities recycle reinvent industrial

Language: Английский

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Post-Polymerization Modification of Polystyrene through Mn-Catalyzed Phosphorylation of Aromatic C(sp²)–H Bonds

ACS Applied Polymer Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 19, 2024

Language: Английский

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Hydroaminoalkylation for Amine Functionalization of Vinyl‐Terminated Polyethylene Enables Direct Access to Responsive Functional Materials

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(49)

Published: Oct. 30, 2024

Abstract While functionalized polyethylenes (PEs) exhibit valuable characteristics, the constraints of existing synthetic approaches limit variety readily incorporated functionality. New methods to generate PEs are required afford new applications this common material. We report 100 % atom economic tantalum‐catalyzed hydroaminoalkylation vinyl‐terminated polyethylene (VTPE) as a method produce amine‐terminated PE. VTPEs with molecular weights between 2200–16800 g/mol successfully aminated using solvent‐free conditions. Our catalytic system is efficient for installation both aromatic and aliphatic amines, can be carried out on multigram scale. The associating amine functional groups modified material properties, measured by water contact angle, differential scanning calorimetry (DSC) polymer rheology. basic functionality offers opportunity convert inert PE into stimuli‐responsive materials, such that protonation affords generation antibacterial films.

Language: Английский

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Upcycling of Polypropylene Wastes via Catalytically C−H Modification with Polar Olefins

ChemCatChem, Journal Year: 2023, Volume and Issue: 16(1)

Published: Sept. 28, 2023

Abstract While polypropylene (PP) is one of the most widely used polyolefin materials, its post‐functionalization has been a continuously researched topic in polymer field since it could significantly improve physical and chemical properties by introducing polar groups, beneficial for development next generation materials. In this work, we describe visible‐light promoted, environmentally friendly iron‐catalyzed strategy establishing reaction scope C−H alkylated modification polypropylene. Under our conditions, various polypropylenes be functionalized with diverse alkenes good levels functionalization (LOF). The resulting polymers were investigated thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile testing. Polypropylene wastes also upcycled. incorporation polyglycol groups enhanced hydrophilicity, installation ester increased miscibility other acting as compatibilizer polystyrene polyethylene.

Language: Английский

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Homogeneous catalysis and heterogeneous separation: Ionic liquids as recyclable photocatalysts for hydroacylation of olefins

Research Square (Research Square), Journal Year: 2024, Volume and Issue: unknown

Published: June 14, 2024

The photoinduced ligand-to-metal charge transfer (LMCT) process has been extensively investigated, however, the recovery of photocatalysts remained a persistent challenge in field. In light this issue, novel approach involving development iron-based ionic liquids as pursued for first time, with goal simultaneously facilitating LMCT and addressing issue photocatalyst recovery. Remarkably, liquid 1-butyl-3-methylimidazolium tetrachloroferrate (C4mim-FeCl4) demonstrates exceptional recyclability stability photocatalytic hydroacylation olefins. This study will pave way new approaches to organic synthesis using recyclable photocatalysts.

Language: Английский

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