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The fabrication of low-cost, recyclable, reusable, and heterogeneous catalysts is of considerable significance for green chemistry. In this study, a nanocomposite catalyst, MCM-41-supported Zn–Co double metal cyanide (MCM-41@DMC), was prepared using the synchronous dropping method. Thereafter, the composition, crystal structure, complexing state, morphology, and thermal stability of the catalyst were characterised using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller analysis, and thermogravimetry. The effects of different organic ligands on the catalytic activity of samples were evaluated, and the results showed that ethyl acetoacetate exhibited the best catalytic activity owing to its ketone coordination. The use of the MCM-41 support was beneficial for improving the catalytic activity because it reduced the crystallinity and substantially increased the external specific surface area of the catalyst. The experimental results pertaining to the use of the MCM-41@DMC catalyst in the fabrication of polypropylene glycol showed that the conversion of propylene oxide and molecular weight reached 90.6% and 2900, respectively. This study provides a new strategy for the green synthesis of poly(propylene glycol) products. [ABSTRACT FROM AUTHOR]

A series of Au–silica (nanosphere) catalysts were prepared by in situ synthesis; highly dispersed gold nanoparticles (GNPs, 6.4 nm) were obtained, and catalytic tests showed good catalytic activity and epoxidation selectivity. To investigate the origin of the GNPs, the solids were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and other instruments. Some reaction parameters, such as solvent, oxidant concentration, catalyst concentration and reaction time, have been investigated and reaction conditions are optimized. [ABSTRACT FROM AUTHOR]

Silk fibroin (SF) is a protein polymer derived from insects, which has unique mechanical properties and tunable biodegradation rate due to its variable structures. Here, the variability of structural, thermal, and mechanical properties of two domesticated silk films (Chinese and Thailand B. Mori) regenerated from formic acid solution, as well as their original fibers, were compared and investigated using dynamic mechanical analysis (DMA) and Fourier transform infrared spectrometry (FTIR). Four relaxation events appeared clearly during the temperature region of 25 °C to 280 °C in DMA curves, and their disorder degree (fdis) and glass transition temperature (Tg) were predicted using Group Interaction Modeling (GIM). Compared with Thai (Thailand) regenerated silks, Chin (Chinese) silks possess a lower Tg, higher fdis, and better elasticity and mechanical strength. As the calcium chloride content in the initial processing solvent increases (1%–6%), the Tg of the final SF samples gradually decrease, while their fdis increase. Besides, SF with more non-crystalline structures shows high plasticity. Two α- relaxations in the glass transition region of tan δ curve were identified due to the structural transition of silk protein. These findings provide a new perspective for the design of advanced protein biomaterials with different secondary structures, and facilitate a comprehensive understanding of the structure-property relationship of various biopolymers in the future. [ABSTRACT FROM AUTHOR]

Abstract: A hybrid complex Zr(PO4)(AgHPO4) was prepared by ion-exchange and was determined using elemental analysis, X-ray diffraction (XRD), Fourier transformed-infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and other instruments. Its catalytic activity was examined on the oxidation of styrene using t-butylhydroperoxide (TBHP) as oxidant under argon atmosphere, this system showed good epoxidation selectivity, the other factors, such as solvent, reaction time, concentrations of oxidant and catalyst, also have been investigated and reaction conditions are optimized. It is a novel highly active/selective and reusable heterogeneous catalyst for styrene epoxidation, while this catalytic system showed no epoxidation selectivity but good enol selectivity for cycloolefins with allylic H. [Copyright &y& Elsevier]

[Display omitted] • A novel ultrasound technique to fabricate flexible protein materials. • Protein structure and properties can be tuned by varying ultrasound power and time. • Biological responses can be controlled by ultrasound-generated protein materials. • Ultrasound technique is a high efficient and easy to operate without any chemical procedures. • Mechanism of ultrasonic effects on protein differents properties are revealed. Ultrasound can be used in the biomaterial field due to its high efficiency, easy operation, no chemical treatment, repeatability and high level of control. In this work, we demonstrated that ultrasound is able to quickly regulate protein structure at the solution assembly stage to obtain the designed properties of protein-based materials. Silk fibroin proteins dissolved in a formic acid-CaCl 2 solution system were treated in an ultrasound with varying times and powers. By altering these variables, the silks physical properties and structures can be fine-tuned and the results were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), gas permeability and water contact angle measurements. Ultrasonic treatment aids the interactions between the calcium ions and silk molecular chains which leads to increased amounts of intermolecular β -sheets and α -helix. This unique structural change caused the silk film to be highly insoluble in water while also inducing a hydrophilic swelling property. The ultrasound-regulated silk materials also showed higher thermal stability, better biocompatibility and breathability, and favorable mechanical strength and flexibility. It was also possible to tune the enzymatic degradation rate and biological response (cell growth and proliferation) of protein materials by changing ultrasound parameters. This study provides a unique physical and non-contact material processing method for the wide applications of protein-based biomaterials. [ABSTRACT FROM AUTHOR]