An Al2O3/MgO composite coating was synthesized on magnesium alloy AZ33 using a chemical conversion process for the first time. EDTA-2Na was introduced in the Al conversion solution to chelate Al3+,...
Fiber materials with multilevel interior structures have myriad applications in many fields due to their unique properties. In this study, we develop a bioinspired flexible ultrafine polymer fiber via an integrated microfluidic-electrospinning technology. The fiber possesses periodic hollow and tubular chambers with a shell layer of approximately 150 nm in thickness extremely like natural bamboo. The single fiber with a diameter of ∼1.5 μm exhibits the Young's modulus ranging from 2 to 7 MPa measured with atomic force microscopy (AFM). The fiber with periodic hollow chambers and extreme toughness can find many applications in medicine, industry, and agriculture.
Water-based or waterborne polyurethane matting resins find extensive application in surface coating to diminish gloss, offering a pleasant tactile experience and a matte aesthetic. This review represents the inaugural effort to consolidate the recent advancements in waterborne polyurethane matting resins, encompassing both physical and chemical matting types. The exploration commences with an introduction to a range of innovative matting agents tailored for the formulation of physical matting waterborne polyurethane resins. Subsequently, a thorough analysis and discussion unfold, delving into the synthesis, characterization, and matting mechanisms of chemical matting waterborne polyurethane resins. This comprehensive discussion draws upon a decade of dedicated research work by our group, contributing fresh perspectives to the evolution of chemical matting techniques. In conclusion, the review not only addresses the current state but also outlines potential challenges and future trends. This forward-looking perspective is intended to offer guidance for the design and synthesis of innovative waterborne polyurethane matting resins.
Abstract This study reports for the first time an innovative pH/magnetic dual-responsive hemicellulose-based nanocomposite hydrogel with a nearly 100% bio-based and biodegradable compositions. We synthesized pure Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 MNPs) using co-precipitation, then engineering xylan hemicellulose (XH), acrylic acid (AA), polyethylene glycol diacrylate (PEGDA), and Fe 3 O 4 MNPs to synthesize the pH/magnetic dual-responsive hydrogel (Fe 3 O 4 @XH-Gel), through free radical graft polymerization on natural XH with in-situ doping Fe 3 O 4 MNPs initiated by the ammonium persulfate/tetramethylethylenediamine (APS/TMEDA) redox system. Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance ( 1 H-NMR), X-ray diffractometry (XRD), scanning electron microscopy and energy dispersive spectrometer (SEM-EDS), Brunauer-Emmett-Teller (BET), dynamic light scattering (DLS), swelling gravimetric analysis, vibrating sample magnetometer (VSM) were employed to analyze the hydrogel’s chemical structures, surface morphologies, pH-responsive behaviors, and magnetic responsiveness characteristics. The results indicate that the Fe 3 O 4 @XH-Gel nanocomposite hydrogel exhibited excellent dual responsiveness to pH and magnetism. Furthermore, an emphasis was placed on the in-depth analysis of the pH response mechanism and drug release control. Finally, we utilized this cutting-edge hydrogel to investigate the controlled-release behavior of two model drugs, Acetylsalicylic acid and Theophylline , within the simulated gastrointestinal tract. The Fe 3 O 4 @XH-Gel nanocomposite hydrogel demonstrated exceptional controlled release attributes, positioning it as a potential carrier for targeted drug delivery, particularly to the gastrointestinal conditions.
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