Magnetite Nanoparticles Functionalized with Thermoresponsive Polymers as a Palladium Support for Olefin and Nitroarene Hydrogenation

A thermoresponsive and recyclable nanomaterial was synthesized by surface modification of magnetite nanoparticles (MNPs) with poly(N-isopropylacrylamide-co-diethylaminoethyl methacrylate) (P(NIPAAm-co-DEAEMA)), having PNIPAAm as a thermoresponsive moiety and PDEAEMA for catalyst binding. Palladium (Pd) nanoparticles were incorporated into this material, and the resulting nanocatalyst was efficient in the hydrogenation of olefins and nitro compounds with turnover frequencies (TOFs) up to 750 h^-1. Consistent catalytic activity in 10 consecutive runs was observed when performing the hydrogenation at 45 °C, i.e., above the lower critical solution temperature (LCST) of the copolymer (37 °C), followed by cooling to 15 °C, i.e., below the LCST of the copolymer.

Novel low-cost carboxymethyl cellulose microspheres with excellent fertilizer absorbency and release behavior for saline-alkali soil

Saline-alkali soil and fertilizer loss severely restrict agriculture on the Songnen Plain in China. To resolve this problem, carboxymethyl cellulose immobilized slow-release fertilizer microspheres (CFM) with homogeneity pore structure, high porosity, biodegradable biological macromolecules and excellent fertilizer absorbency were synthesized by the combination of inverse emulsion polymerization and microfluidic method. By optimizing the synthesis conditions, the water absorption of CFM reached 8725 g g^-1 in deionized water. The absorbency behaviors of CFM were highly sensitive to pH, ionic strength, and ionic species. In 5 g L^-1 urea solution, the adsorption capacity of CFM was 3342.84 g g^-1. The CFM showed excellent urea retention at 80 °C for 5 h and sustained release performance in soil. Besides, degradation rate of CFM was closed to 98.2% in Aspergillus niger at the third day. CFM had the advantages of high pH sensitivity, salt resistance, and good fertilizer absorbency and retention. Therefore, it will be prospecting fertilizer sustained release agent in agriculture.

Controllable Synthesis of Monolayer Poly(acrylic acid) on the Channel Surface of Mesoporous Alumina for Pb(II) Adsorption

Polymer/inorganic nanocomposites exhibit special properties due to highly intimate interactions between organic and inorganic phases and thus have been deployed for various applications. Among them, nanocomposites with monolayer polymer coverage on the inorganic surface demonstrate the highest efficiency for applications. However, the controllable synthesis of the polymer monolayer in mesopores of inorganic substrates remains a challenge. In this study, poly(acrylic acid)/γ-alumina nanocomposites (PAA/alumina) were synthesized via the in situ polymerization of acrylic acid impregnated in mesopores of alumina. By applying the preneutralization of monomers, the polymerization was found to be highly controllable in generating monolayer PAA coverage. The formation of monolayers was verified by thermogravimetry, semiquantitative Fourier transform infrared spectroscopy, N₂ adsorption-desorption, and Pb(II) adsorption. Alternatively, the organic loadings of PAA/alumina composite samples could be controlled in the range of 0.2 to 1.0 equiv of monolayer, together with the linearly correlated metal ion adsorption capacity. As calculated by the complexation model, one Pb(II) is combined with two carboxylate groups of PAA. The formation of the monolayer polymer inside mesoporous oxide channels represents a method for the development of highly promising functional nanocomposites.

Comparative Evaluation of Biological Performance, Biosecurity, and Availability of Cellulose-Based Absorbable Hemostats

Hemorrhage remains a leading cause of death after trauma, and developing a hemostat with excellent performance and good biosecurity is an extremely active area of research and commercial product development. Although oxidized regenerated cellulose (ORC) has been developed to address these problems, it is not always efficient and its biosecurity is not perfect. We aimed to refine ORC via a simple and mild neutralization method. The prepared neutralized oxidized regenerated cellulose (NORC) showed a superior gel property due to its chemical structure. The biological performance of both ORC and NORC was systematically evaluated; the results showed that ORC would induce erythema and edema in the irritation test, whereas NORC did not cause any adverse inflammation, indicating NORC had desirable biocompatibility. We further demonstrated that NORC confirmed to the toxicity requirements of International Organization for Standardization (ISO) standards; however, ORC showed an unacceptable cytotoxicity. The rabbit hepatic defect model stated that NORC exhibited better ability of hemostasis, which was attributed to its significant gel performance in physiological environment.

Mussel-inspired facile synthesis of Fe/Co-polydopamine complex nanospheres: complexation mechanism and application of the carbonized hybrid nanospheres as an efficient bifunctional electrocatalyst

A one-pot synthesis of Co(ii)–Fe(iii)–PDA complex nanospheres as a facile approach to obtain binary metal-doped carbon nanostructures.