Novel Preparation of Polyethylene from Nano‐extrusion Polymerization Inside the Nanochannels of MCM‐41/MgCl2/TiCl4 Catalysts

The MCM‐41 and SiO₂ supported TiCl₄ and TiCl₄/MgCl₂ catalysts with different molar ratios of Mg/Ti were synthesized and used for ethylene polymerization under atmospheric pressure. The nanochannels of MCM‐41 serve as nanoscale polymerization reactor and the polyethylene nanofibers were extruded during the reaction. The nanofibers were observed in SEM micrographs of resulting polyethylene. The effect of MgCl₂ on catalytic activity and thermal properties of resulting polyethylene is investigated too. In the presence of MgCl₂, the catalytic activity increased and more crystalline polyethylene with higher melting points were formed. However, no fibers could be observed in the polyethylene prepared by SiO₂ supported catalysts.     

Unusual Extensional Rheology and Dispersion Behavior of High Impact Polystyrene/TiO2 Nanocomposites Prepared by Melt‐Compounding

The extensional rheology and dispersion behavior of high impact polystyrene (HIPS) and HIPS/TiO₂ nanocomposites prepared by melt‐compounding were investigated. The influence of ethylene‐vinyl acetate (EVA) copolymer on the extensional rheology of HIPS/TiO₂ masterbatches was also researched. The rheological experiments investigated with Rosand Presicion Rheometer confirmed that the HIPS/TiO₂ masterbatches, the HIPS/EVA/TiO₂ masterbatches and the HIPS/TiO₂ nanocomposites with low TiO₂ loading shown different extensional rheology in comparison to the pure HIPS. Field‐emission scanning electron microscopy (FE‐SEM) shown the dispersion morphology of TiO₂ nanoparticles in HIPS based nanocomposites and indicated the influence of TiO₂ dispersion behavior on the unusual extensional rheology of HIPS nanocomposites.     

Hydrogenation of Furfural to Furfuryl Alcohol over Co-B Amorphous Catalysts Prepared by Chemical Reduction in Variable Media

Five Co-B amorphous alloy catalysts were prepared by chemical reduction in different media, including pure water and pure ethanol as well as the mixture of ethanol and water with variable ethanol content, Their catalytic properties were evaluated using liquid phase furfural hydrogenation to furfuryl alcohol as the probe reaction. It was found that the reaction media had no significant influence on either the amorphous structure of the Co-B catalyst or the electronic interaction between metallic Co and alloying B. This could successfully account for the fact that all the as-prepared Co-B catalysts exhibited almost the same selectivity to furfuryl alcohol and the same activity per surface area （ Rs ）, which could be considered as the intrinsic activity, since the nature of active sites remained unchanged. However, the activity per gram of Co （ R^mH ） of the as-prepared Co-B catalysts increased rapidly when the ethanol content in the water-ethanol mixture used as the reaction medium for catalyst preparation increased. This could be attributed to the rapid increase in the surface area possibly owing to the presence of more oxidized boron species which could serve as a support for dispersing the Co-B amorphous alloy particles.     

Characterization of Ni／AlMCM-41 Catalysts and Their Catalytic Performance in n-Dodecane Hydroconversion

A series of Ni/AIMCM-41 catalysts with different nickel contents was prepared via the incipient wetness impregnation method. The effects of the nickel content on the structure, acidity and metal function of the catalysts were studied by using different techniques. In the test of n-dodecane hydroconversion, it was found that the metal and acid functions were well balanced over a 2.0%Ni (mass fraction)/AIMCM-41 catalyst, which gave the maximal isomerization selectivity and a homolytic cleavage products.     

Effect of TiO2 Support on the Composition, Morphology and Catalytic Property of the NiB Amorphous Alloy Catalyst

Both the unsupported and supported NiB amorphous alloy catalysts (NiB and NiB/TiO2)were prepared by the chemical reduction method. Their catalytic activities were tested by thehydrogenation of sulfolene. The interactions between the NiB alloy and TiO2 were discussed forthe first time by using XRD, ICP, SEM and TEM.     

Activation of the Surface of Carbon and Nitrogen-Doped Carbon Nanotubes by Calcium Nitrate: Catalytic Properties of Cobalt Supported Catalysts of the Fischer–Tropsch Process Based on Them

Kinetics and Catalysis - Using the methods of scanning and transmission electron microscopy (SEM and TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, the influence of...     

Physicochemical and Catalytic Properties of Ni,H/ZSM-5 and Ni,H/ZSM-5–Binder Catalysts Prepared in the Absence and in the Presence of Binder

Kinetics and Catalysis - Physicochemical and catalytic properties of H/ZSM-5 and Ni,H/ZSM-5 along with Ni,H/ZSM-5–Al2O3 (1 : 1) systems were examined. The systems with a binder were prepared...