FT-Raman analysis of the effects of γ-radiation on nylon 6–12 filaments

Summary FT-Raman spectroscopy of commercial amorphous and crystalline nylon 6–12 filaments subjected to various -radiation doses are presented. The results show that a difference exists in the interaction of -radiation with these polyamides, depending on the crystallinity which can be evaluated by measuring the CH-stretching/CH-bending Raman band intensity ratio as a function of applied -dose.     

Coal liquefaction by in-situ hydrogen generation.: 1. Zinc-water-coal reaction

Liquefaction of coal was carried out in a zinc—water—solvent system to give a product with high concentration of pyridine and benzene solubles. In this system the metal reacts with water to produce the corresponding metal oxide and hydrogen. This hydrogen was used for in-situ hydrogenation of coal. The effects of reaction time, temperature, type of solvent, the quantity of metal used and the rank of coal were investigated. The solvent has a very marked effect on the conversion of coal to benzene-soluble materials, especially at short reaction times. A maximum benzene conversion of 96% for Taiheiyo coal was obtained when it was treated at 445 °C for 1 h using wash oil as solvent. With regard to the influence of coal rank it was found that low rank coals were more reactive than high rank coals. The amount of preasphaltene is only slightly influenced by coal rank but depends on the temperature and the type of solvent used.     

Evaluation of different amine‐functionalized polyethylenes as compatibilizers for polyethylene film nanocomposites

The compatibilization effects provided by different amine‐functionalized polyethylenes (PEs) versus those provided by a maleated polyethylene (PEgMA), for forming PE‐based film nanocomposites, were studied. Amine‐functionalized PEs were prepared by reaction of PEgMA with two primary amines, 2‐aminoethanol (EA) and 1,12‐aminododecane (D12), and a tertiary amine, 2‐[2‐(dimethylamino)ethoxy]ethanol (DMAE), in the melt to form the corresponding PEgEA, PEgD12 and PEgDMAE. Nanocomposites were prepared by melt mixing in a twin‐screw extruder PE and these three functionalized compatibilizers with a modified montmorillonite clay. The purpose of the current work was to determine the effect of the various amine‐functionalized PEs on the degree of exfoliation and optical properties of PE–clay nanocomposites in order to obtain nanocomposite films for greenhouse cover applications. Fourier transform infrared analysis confirmed the formation of the amine‐modified PE compatibilizers. Structural, morphological, mechanical, rheological and optical properties of film samples were used to characterize the nanocomposites. All the amine‐modified PE‐compatibilized nanocomposites had better clay exfoliation compared to uncompatibilized PE composites. Results showed that PEgDMAE formed highly exfoliated morphology and a favorable balance between mechanical (stiffness and ductility), optical and thermal insulating film properties even at higher clay contents. It was determined that nanocomposites with greater exfoliated structure showed better optical and thermal insulating film properties. PEgEA and PEgD12 compatibilizers did not provide a better interaction for exfoliation of the organoclay than the PEgMA material. The PEgDMAE compatibilizer led to a highly exfoliated morphology and a favorable balance between mechanical, optical and thermal insulating film properties even at higher clay contents. The PEgDMAE film nanocomposites could be used ideally for greenhouse cover applications. Copyright © 2010 Society of Chemical Industry     

Modeling of Drying Curves of Silica Nanofluid Droplets Dried in an Acoustic Levitator Using the Reaction Engineering Approach (REA) Model

The use of nanoparticles has become of great interest in different industrial applications. The spray drying of nanofluids forms nanostructured grains, preserving the nanoparticle properties. In this work, individual droplets of silica nanofluids were dried in an acoustic levitator. Tests were carried out under different experimental conditions to study the influence of the variables on the drying process. The drying curves were experimentally obtained and an REA model was used to obtain the theoretical curves and the correlations for the activation energy. The critical moisture content theoretically obtained was used to predict the grain diameter.     

H2-Production on New BaTi(1−x)RhxO3 Catalyst via the Steam Reforming of CH4 for H2-SCR Applications

Rh-doped perovskites BaTi_0.9Rh_0.1O₃ and Rh–BaTiO₃ were prepared by a new synthesis method and analyzed by XRD and FE-scanning electron microscopy (SEM). The effect of HCl for sol-formation was studied, HCl improves the sol formation but chlorine remains in the catalyst even after calcination treatment at 1,000 °C. Cl-free catalysts were prepared and analyzed on reactions for H₂ production which can be used for H₂-SCR reactions. The Rh-integrated perovskite BaTi_0.9Rh_0.1O₃ displayed better catalytic performance compared to Rh–BaTiO₃ and Rh–TiO₂ under the studied reaction conditions. Carefull XRD analysis was carried out to demonstrate the incorporation of Rh in the perovskite lattice. Rhodium reacts with the tetragonal perovskite BaTiO₃ to stabilize the hexagonal modification. Mainly, the hexagonal perovskite was found in the catalyst BaTi_0.9Rh_0.1O₃. This modification appears only after Rh-impregnation and calcination of the tetragonal BaTiO₃ thus coexisting the hexagonal perovskite BaTi_(1?x)Rh_xO₃ and the tetragonal BaTiO₃. The catalysts reduction in diluted H₂ containing gas mixtures cause the segregation of Rh° nanoparticles out of the perovskite crystal lattice.     

The effect of thermoplastic starch on the properties of HDPE/TPS blends during UV-accelerated aging

The influence of thermoplastic starch (TPS) on the properties of UV-irradiated TPS/high-density polyethylene (HDPE) blends was investigated. Changes in chemical structure, molecular weight, crystallinity, and mechanical properties, as a function of exposure time, were determined using FTIR-spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and tensile tests. The inclusion of TPS influence neither the evolution of carbonyl index nor the molecular weight reduction of HDPE/TPS. In contrast, the presence of TPS in the blends increased the fusion enthalpy because of starch retrogradation. This increasing resulted in a corresponding increase of Young??s modulus of HDPE/TPS blends.