Search

Rational engineering active sites and vantage defects of catalysts are promising but grand challenging task to enhance photoreduction CO2 to high value‐added C2 products. In this study, we designed an N,S‐codoped Fe‐based MIL‐88B catalyst with well‐defined bipyramidal hexagonal prism morphology via a facile and effective process, which was synthesized by addition of appropriate 1,2‐benzisothiazolin‐3‐one (BIT) and acetic acid to the reaction solution. Under simulated solar irradiation, the designed catalyst exhibits high C2H4 evolution yield of 17.7 μmol g−1⋅h, which has been rarely achieved in photocatalytic CO2 reduction process. The synergistic effect of Fe‐N coordinated sites and reasonable defects in the N,S‐codoped photocatalyst can accelerate the migration of photogenerated carriers, resulting in high electron density, and this in turn helps to facilitate the formation and dimerization of C−C coupling intermediates for C2H4 effectively. [ABSTRACT FROM AUTHOR]

The anti‐migration ethylene propylene diene terpolymer (EPDM) inhibitor coating was prepared by using EPDM as a composite matrix and silicon‐functionalized graphene oxide (GO‐SiO2) as modifiers to prevent the migration of energetic plasticizers in propellants. The anti‐migration performance at different temperatures was analyzed by investigating the diffusion of dioctyl sebacate (DOS) using thermal analysis and immersion tests. After adding 1.0 wt% GO‐SiO2, the overall performance of the inhibitor coating was the best, and the concentration of DOS that migrated into the inhibitor coating at 30°C was reduced from 45.1% to 38.8% (13.9% decrease). The results confirmed that the introduction of GO‐SiO2 prevented the migration of dioctyl sebacate to the EPDM inhibitor coating. The scanning electron microscopy results showed that GO‐SiO2 was well‐dispersed in the inhibitor coating, and the tensile strength increased from 1.80 to 2.11 MPa. Migration kinetics analysis showed that the anti‐migration performance was closely related to the crosslink density. [ABSTRACT FROM AUTHOR]

ABSTRACT A series of novel cyclic olefin copolymers (COCs), including ethylene/tricyclo[4.3.0.12,5]deca-3-ene (TDE), ethylene/tricyclo[4.4.0.12,5]undec-3-ene (TUE), and ethylene/tricyclo[6.4.0.19,12]tridec-10-ene (TTE) copolymers, have been synthesized via effective copolymerizations of ethylene with bulk cyclic olefin comonomers using bis(β-enaminoketonato) titanium catalysts ( 1a [PhNC(CH3)CHC(CF3)O]2TiCl2; 1b: [PhNC(CF3)CHC(Ph)O]2TiCl2). With modified methylaluminoxane as a cocatalyst, both catalysts exhibit high catalytic activities, producing high molecular weight copolymers with high comonomer incorporations and unimodal molecular weight distributions. The microstructures of obtained ethylene/COCs are established by combination of 1H, 13C NMR, 13C DEPT, HSQC 1H13C, and 1H1H COSY NMR spectra. DSC analyses indicate that the glass transition temperature ( Tg) increases with the enhancement of comonomer volume (TDE < TUE < TTE). High Tg value up to 180 °C is easily attained in ethylene/TTE copolymer with the low content of 35.8 mol %. TGA analyses reveal that these copolymers all possess high thermal stability with degradation temperatures ( Td) higher than 370 °C in N2 and air. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3144-3152 [ABSTRACT FROM AUTHOR]