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Disentangled ultra-high-molecular-weight polyethylene (-UHMWPE) solves the problem of the difficult processing of traditional UHMWPE caused by entanglements between molecular chains. In this review, we look into the innovative realm of nascent disentangled UHMWPE, concentrating on the recent advances achieved through the in situ polymerization of ethylene by single-site catalysts. The effect of single-site catalysts and polymerization conditions on the molecular characteristics is discussed in detail from the perspective of mechanism and DFT calculations. The key factors to low entanglement are revealed, which have instructive implications for the development of new single-site catalytic systems that can generate -UHMWPE more efficiently and become closer to industrial production. The progress in the preparation for nascent -UHMWPE with homogeneous and heterogeneous single-site catalysts is systematically reviewed. Rheology and DSC can be used to characterize the degree of entanglement. High-modulus and high-strength biaxial films, tapes, and fibers are obtained by the solid-state processing of these nascent -UHMWPE.
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http://dx.doi.org/10.3390/polym17010095 | DOI Listing |
ACS Appl Mater Interfaces
September 2025
Leibniz-Institut für Katalyse e.V. (LIKAT), Albert-Einstein-Str. 29a, Rostock 18059, Germany.
Metal-organic frameworks (MOFs) are transformative platforms for heterogeneous catalysis, but distinguishing atomically dispersed metal sites from subnanometric clusters remains a major challenge. This often demands the integration of multiple characterization techniques, many of which either lack the resolving power to distinguish active sites from their surrounding environments (e.g.
View Article and Find Full Text PDFNat Chem
September 2025
Department of Chemistry and the Trienens Institute for Sustainability and Energy, Northwestern University, Evanston, IL, USA.
Current methods of processing accumulated polyolefin waste typically require harsh conditions, precious metals or high metal loadings to achieve appreciable activities. Here we examined supported, single-site organonickel catalysts for polyolefin upcycling. Chemisorption of Ni(COD) (COD, 1,5-cyclooctadiene) onto Brønsted acidic sulfated alumina (AlS) yields a highly electrophilic Ni(I) precatalyst, AlS/Ni(COD), which is converted under H to the active AlS/NiH catalyst.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2025
Frontiers Science Center for New Organic Matter, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), State Key Laboratory of Advanced Chemical Power Sources, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai Univers
The methanol oxidation reaction serves as a representative model for multistep catalytic processes involving diverse intermediates. Catalyst design strategies that spatially arrange discrete active sites, analogous to relay runners, facilitate the sequential activation of reaction steps, thereby enhancing overall catalytic efficiency compared to single-site catalysts. This approach effectively decouples complex reaction networks into a sequence of coordinated elementary steps, thereby enhancing the production efficiency of the target products.
View Article and Find Full Text PDFJ Am Chem Soc
August 2025
National Engineering Research Center of Lower-Carbon Catalysis Technology, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
The catalytic coupling conversion of naphtha and CO to aromatics over metal-zeolites offers a fascinating route for aromatics production, yet, the exploitation of efficient metal-zeolite catalysts and CO coupled naphtha to make CO transformed into high-value-added chemicals remain great challenges. Herein, we synthesized a framework-anchored Ga-MFI catalyst synthesized ligand-assisted hydrothermal crystallization, achieving 80.76% aromatic selectivity at 99.
View Article and Find Full Text PDFChemSusChem
August 2025
School of Chemistry and Chemical Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education), Hubei Key Laboratory of Material Chemistry and Service Failure, Wuhan National Labora
Single-site catalysts (SSCs) have attracted increasing attention due to their ultrahigh atomic utilization and intrinsic catalytic activity in water electrolysis. However, the low volumetric density of SSCs on bulk supports limits the overall activity. Coupling porous supports with SSCs (PS-SSCs) can synergistically achieve exponential performance improvements.
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