Journal of Particle Science and Technology
Volume:1 Issue: 1, Winter 2015

Thermoplastic polyurethane (TPU)/clay nanocomposites were prepared via a melt-compounding method using ester type TPU and two different modified organoclays (Cloisite 30B and Cloisite 15A) in different contents. The Effects of the chemical structure and content of the nanoclays on the thermal degradation and mechanical properties of TPU were also investigated. The effect of structural modification on dispersion during melt compounding has been studied by XRD and FTIR analysis. Barrier effect formation and thermal stability in both nanocomposites containing different nanoparticle content have been studied. The effect of chemical modification of the nanoparticles on mechanical properties in all contents has been investigated. The XRD results show that better dispersion near the exfoliated structure obtained for cloisite 30B is due to good interaction via hydrogen bonding between the TPU chains and layered silicate. A high content of the nanoparticles leads to disordering of soft and hard segments in the TPU chains, which is confirmed by FTIR. Mechanical properties analysis shows that the TPU/Cloisite 30B nanocomposites have higher modulus and tensile strength as well as elongation at break by the addition of 2% in both cloisite 30B (C30B) and cloisite 15A (C15A) than other contents of nanoclays.

In this work the kinetic data demanded for kinetic modeling were obtained in temperatures 350, 400, 450 and 500 oC by conducting experimentations on a Fe-Cr nanocatalyst prepared from a novel method and a commercial Fe-Cr-Cu one. The collected data were subjected to kinetic modeling by using two models derived from redox and associative mechanisms as well as an empirical one. The coefficients obtained for H2O reduction to H2 was much higher than those resulted for CO oxidation to CO2. In addition, the rate of H2O adsorption was shown to be greater than that of the CO adsorption on the catalyst surface in various temperatures. The activation energy of the novel catalyst calculated from the empirical model constants was lower than that of the commercial one.

The mononuclear Gd(III) complex, [Gd(L)3(H2O)5] (where L is alizarin yellow R (NaC13H8N3O5)), has been prepared in H2O under reflux condition. The Gd(III) complex has been characterized by elemental analysis and spectroscopic methods (UV–Vis and FT–IR). The Gd2O3 nanoparticles were prepared by the calcination of the Gd(III) complex in air at different temperatures up to 600 °C for 2 h. The calcination temperature was the key parameter which was changed for more investigation. The products were characterized by various methods such as FT–IR, X-ray diffraction analysis and field-emission scanning electron microscopy (FE–SEM). The electrochemical studies of the Gd(III) complex and Gd2O3 nanoparticles were performed in acetonitrile. The voltammograms in the absence and presence of carbon dioxide indicate that [Gd(L)3(H2O)5] and Gd2O3 nanoparticles can catalyze the electrochemical reduction of CO2 to CO.

In recent years, the effects of heterogeneous catalysts for the oxidation of organic and inorganic pollutants in industrial wastewaters are spread. Traditionally, these reactions are usually carried out using suspensions of photo-catalysts such as TiO2. A chemical method including TiCl4, Al(NO3)3, ethanol amine, ethyl acetoacetate and aqueous ammonia were used for the fabrication of TiO2-Al2O3 nano-composite. The as prepared nano-composite was characterized applying the XRD, FE-SEM and TEM techniques. The photocatalytic behavior of TiO2-Al2O3 nano-composite was evaluated in the photo-catalytic degradation of methyl orange under UV irradiation technique. The effect of various parameters including catalyst dosage, dyes concentration, pH and temperature on the degradation of methyl orange was investigated. The degradation rate was efficiently increased as the concentration of catalyst was decreased. The optimum dosage of methyl orange was found to be 10 mgL-1. In addition, we found that pH can significantly enhance the photocatalytic degradation of methyl orange dye.

In this work, ternary polymer blends based on polypropylene (PP)/ polyethylene terephthalate (PET) /poly(styrene-b (ethylene-co-butylene)-b-styrene) (SEBS) triblock copolymer and a reactive maleic anhydride grafted SEBS (SEBS-g-MAH) at various compositions were prepared by co-rotating twin screw extruder. The effects of PET, SEBS and SEBS-g-MAH compatibilizer on morphology of the blends were examined by scanning electron microscopy (SEM). The blends morphology was also estimated by some predicting methods, however, SEM results revealed some contrasts between results of predicting methods and the real morphology. Population of individual and core-shell particles as well as average diameter of the rubber-based cavities is extremely dependent on SEBS, SEBS-g-MA and PET content. Mechanical inspection tests showed that in comparison with the pure PP, addition of SEBS/SEBS-MA causes an increase in the impact strength of the system. Keeping other parameters constant, with increase in SEBS rubbery phase, the core-shell morphology was affected and the impact strength increased consequently. On the other hand, increase in PET content results in modulus increase and the impact strength decrease. Finally, the optimum processing conditions for compounding ternary PP/PET/SEBS blends were achieved.

In order to investigate the gas separation ability of a column packed with nanozeolitic material, nano NaY zeolite was synthesized and granulated. These uniform granules packed in a chromatographic column were utilized for separation of Xe and Kr under various operating conditions. With regards to the response peaks obtained from trace injections of Xe and Kr into the column, the first and second normalized moments of peaks were calculated. Moreover, the height equivalent to a theoretical plate (HETP) for the column was determined. The results illustrated that the retention time of Xe was remarkably greater than Kr indicating that, the nano NaY zeolite was a good choice as an adsorbent in Kr and Xe separation process. Moreover, a simple and temperature dependent correlation was derived to predict the HETP for the packed column. Ultimately, the calculated HETP values were in a good agreement with experimental data.

The flame propagation through a coal dust-air mixture in a spherical vessel was studied by means of a one-dimensional, Arrhenius-type kinetics and quasi-steady model. The model includes the evaporation of the volatile matter of dust particles into a known gaseous fuel (methane) and the single-stage reaction of the gas-phase combustion. Effect of venting devices as safety idea and the radiation heat loss, as very affecting phenomenon on flame propagation speed, flame temperature and pressure were studied. The radiation heat losses occur between the reaction zone and the surrounding wall. Influence of dust concentration and dust volatility on dust explosion parameters has been analyzed. The pressure-time curves that are generated with this model show a good similarity with those measured in practice. The model can represent a useful framework to be employed in organic dust combustion. This research can be valuable in the development of alternative fuels; and it can be used by the fire safety and control industry.