We finely designed a set of [2]rotaxanes with urea threads and tested them as hydrogen-bonding phase-transfer catalysts in two different nucleophilic substitutions requiring the activation of the reactant fluoride anion. The [2]rotaxane bearing a fluorinated macrocycle and a fluorine-containing urea thread displayed significantly enhanced catalytic activity in comparison with the combination of both noninterlocked components. This fact highlights the notably beneficial role of the mechanical bond, cooperatively activating the processes through hydrogen-bonding interactions.
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http://dx.doi.org/10.1021/jacs.4c06630 | DOI Listing |
Sci Bull (Beijing)
January 2025
Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Hubei Provincial Engineering Research Center of Emerging Functional Coating Materials, School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China. Electronic address:
The discontinuous fiber reinforced hydrogels are easy to fail due to the fracture of the fiber matrix during load-bearing. Here, we propose a novel strategy based on the synergistic reinforcement of interconnected natural fiber networks at multiple scales to fabricate hydrogels with extraordinary mechanical properties. Specifically, the P(AA-AM)/Cel (P(AA-AM), poly(acrylic acid-acrylamide); Cel, cellulose) hydrogel is synthesized by copolymerizing AA and AM on a substrate of paper with an interconnected hollow cellulose microfiber network.
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January 2025
School of Civil Engineering and Environmental Science, University of Oklahoma, 202 W Boyd St., Norman, OK 73019, USA.
With 3D printing technology, fiber-reinforced polymer composites can be printed with radical shapes and properties, resulting in varied mechanical performances. Their high strength, light weight, and corrosion resistance are already advantages that make them viable for physical civil infrastructure. It is important to understand these composites' behavior when used in concrete, as their association can impact debonding failures and overall structural performance.
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January 2025
Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, 1-8-14 Kandasurugadai, Chiyoda-ku, Tokyo 101-8308, Japan.
Calcified tissues in living organisms, such as bone, dentin, and enamel, often require surgical intervention for treatment. However, advances in regenerative medicine have increased the demand for materials to assist in regenerating these tissues. Among the various forms of calcium phosphate (CaP), tricalcium phosphate (TCP)-particularly its α-TCP form-stands out due to its high solubility and efficient calcium release, making it a promising candidate for bone regeneration applications.
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January 2025
Institute for Preservation and Conservation of Chinese Ancient Books, Fudan University Library, Fudan University, 220 Handan Road, Shanghai 200433, China.
Paper-based cultural relics experience aging and deterioration during their long-term preservation, which poses a serious threat to their lifetime. The development of conservation materials with high compatibility and low intervention has been expected to extend the lifetime of paper artifacts. As a new type of biological macromolecule, nanocellulose has been extensively utilized in paper conservation, attributed to its excellent paper compatibility, high optical transparency, outstanding mechanical strength, and large specific surface area with abundant hydroxyl groups.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
School of Physical and Technology, Wuhan University, Wuhan 430072, China.
Aluminum and its alloys are widely used in the busbar structures of electrolytic aluminum production. However, they are prone to corrosion and wear damage during use, leading to a decline in current-transmission efficiency and potentially causing safety issues. To repair damaged aluminum busbars, this paper explores the feasibility of using cold spraying technology for surface restoration.
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