Search

ABSTRACT: A cyclic N‐halamine precursor, 4‐ethyl‐4‐(hydroxymethyl)oxazolidin‐2‐one (EHMO), was synthesized and attached to poly(methylhydrosiloxane) (PMHS) through silane alcoholysis between the OH of EHMO and SiH of PMHS. The alcoholysis product was chlorinated with tert‐butyl hypochlorite to transfer the NH to NCl and obtain an EHMO‐based N‐halamine polysiloxane. The N‐halamine polysiloxane was impregnated into inert polypropylene (PP) fibers and formed a 72 nm coating layer using supercritical carbon dioxide (scCO2) as solvent and swelling reagent at 28 MPa and 50 °C for biocidal application. The overall synthetic procedure and the impregnation process were characterized by FTIR, XPS, and SEM, respectively. The N‐halamine polysiloxane layer on PP imparted potent antibacterial abilities against both Staphylococcus aureus and Escherichia coli while pristine ones did not exhibit noticeable killing activities. Stability tests showed that the N‐halamine polysiloxane layer was resistant to washing cycles, storage, and UV irradiation and the rechlorination of lost chlorines was good. The strategy of using CO2‐philic PMHS as carrier polymer and scCO2 as working solvent for impregnation presents a general and friendly procedure to functionalize inert substrates without the need of chemical linkage and organic solvent. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46624. [ABSTRACT FROM AUTHOR]

In order to investigate the effects of Sm2O3 as a promoter on catalytic performance, ordered mesoporous NiO–Sm2O3–Al2O3 catalysts were synthesized by a facile one-pot evaporation-induced self-assembly (EISA) method and used in the CO methanation reaction to produce synthetic natural gas. Besides, the ordered mesoporous catalysts prepared by the conventional impregnation method together with unordered mesoporous catalysts were selected as references. These catalysts were characterized by scanning electron microscopy, transmission electron microscopy, N2 adsorption, X-ray diffraction, H2 temperature-programmed reduction, X-ray spectroscopy, and thermogravimetric analysis. The results revealed that the ordered mesoporous catalysts synthesized by the one-pot EISA method showed enhanced catalytic performance for CO methanation compared with those prepared by the impregnation method. The addition of the Sm species can further improve the catalytic activity, and the ordered mesoporous 20N6SOMA catalyst with 20 wt% NiO and 6 wt% Sm2O3 species was the best. Our characterization results showed that Sm2O3 could improve the reducibility of Ni particles and decrease the Ni particle sizes; the majority of Sm species were in the form of Sm3+ (Sm2O3) together with a small amount of Sm2+ (SmO) over the reduced catalysts. The Sm3+/Sm2+ redox could increase the electron cloud density of Ni, which resulted in intensified catalytic activity over the ordered mesoporous NiO–Sm2O3–Al2O3 catalyst. Moreover, the optimal ordered mesoporous 20N6SOMA catalyst showed high stability in a 101 h lifetime test at 550 °C and 0.1 MPa due to its excellent confinement effect. [ABSTRACT FROM AUTHOR]