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41.
Erfan Zabihi Hoomaan Joz Majidi Sina Kazemi Pasarvi Dina Shahrampour Morteza Khomeiri 《Journal of Macromolecular Science: Physics》2013,52(10):645-659
ZnO nanoparticles were synthesized through a cost-effective and safe method followed by fabrication and characterization of polyethylene/ZnO nanocomposite films and investigation of their properties. The morphology and size of the synthesized nanoparticles were evaluated by field emission scanning electron microscopy (FE-SEM). It was found that nanoparticles with a plate-like morphology with an average thickness of 50-70?nm were synthesized. The nanocomposites were characterized by using Fourier transform infrared analysis (FTIR) and ultraviolet–visible spectroscopy (UV-VIS). In addition, the effects of the amount of zinc oxide nanoparticles (ZnO-NPs) on the mechanical properties of the films and particles and their antibacterial properties against a gram-negative bacterium (Escherichia coli) and gram-positive bacteria (Staphylococcus aureus) were investigated. In the case of nanoparticles, one more gram-positive bacterium (Staphylococcus aureus) was studied. The results demonstrated an inhibition of growth of all bacteria in a broth medium for both the nanoparticles and nanocomposites. The FE-SEM micrographs revealed that by increasing the nanofiller content an inferior quality of dispersion was obtained which was reflected in the lower tensile strength of the nanocomposites compared to the pure PE. It was demonstrated that the addition of poly ethylene graft maleic anhydride (PE-g-MA), as compatibiliser, improved the dispersion state of the nanoparticles and, consequently, the ultimate mechanical properties. In addition, it was shown that the fabricated nanocomposites exhibited considerable UV-shielding properties. 相似文献
42.
Erfan Ghashghaei Somayyeh Kheirjou Sara Asgari Hanif Kazerooni 《Comptes Rendus Chimie》2018,21(9):862-871
Two different ternary nanocomposites, PPy/CNT/CoFe2O4 and PPy/CNT/NiFe2O4, were synthesized by in situ polymerization method. The resulting composites were characterized using Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. They were evaluated with the aim of investigating microwave absorption properties. The results showed that the value of microwave reflection decreases as that of prepared nanocomposites increases. This happens with increase in the PPy content and polymerization on the surface. 相似文献
43.
季戊四醇酯难燃绝缘油的研究陈尔凡,肖毅,徐新(沈阳化工学院高分子化工系沈阳110021)关键词 难燃绝缘油,季戊四醇酯,C_(5-9)混合酸,酯化反应普通绝缘油(矿物油)耐热性差(闪点低),且使用寿命短。故国际上大力开展了难燃绝缘油的研制[1~5],... 相似文献
44.
Mohammad Kalhor Nikou Hamzehpour Erfan Ghashghaei Mohammad Faridi Hamideh Kalhor 《International Journal for Ion Mobility Spectrometry》2016,19(2-3):139-144
Triazine herbicides and some of their transformation products are considered as one of the most important classes of chemical pollutants owing to their widespread use and toxicity. Triazines and their degradation products have caused concern because they are toxic and persistent in water, soil, and organisms. The present paper describes the validation of ultrasound-assisted emulsification-microextraction (USAEME) method for determination of atrazine and simazine using ion mobility spectrometry (IMS) in environmental water. The parameters influencing the extraction efficiency such as sonication time, extraction solvent, extraction volume and salt concentration were investigated. Under the optimum conditions, enrichment factors was 170 and 150 with corresponding LOD of 8 and 12 μg/L for atrazine and simazine respectively . Linearity with a coefficient of estimation (r2) were >0.99 in the concentration level range of 15–1500 μg/L and 20–1700 μg/L for extraction of atrazine and simazine in water samples. The proposed method successfully was applied to screen of atrazine and simazine in environmental water. 相似文献
45.
In the present study, a series of bioresource polyelectrolytes based on chitosan were synthesized and assessed for applicability in direct methanol fuel cells (DMFCs). A binary cross‐linking agent (sulfosuccinic acid/glutaraldehyde) was used for the structural modification of chitosan and membranes comprising various amounts of sulfosuccinic acid (0, 8, 12, and 16 wt% SSA/wt chitosan) were prepared. It was found that by increasing the sulfonate groups' content up to 16 wt%, proton conductivity and methanol permeability properties reach the values of 0.0452 S cm?1 and 9.6 × 10?7 cm2 sec?1, respectively. Based on the membrane selectivity evaluation and activation energy measurements of proton conduction, the optimum composition of cross‐linking agent was determined. The optimum composition resulted in a relatively high proton conductivity of 0.0452 S cm?1 and a low methanol permeability of 9.6 × 10?7 cm2 sec?1. Moreover, the optimum proton exchange membrane exhibited selectivity value of 47,100 in comparison with the corresponding value of 40,500 for Nafion® 117. The fabricated membranes showed acceptable oxidative and hydrolytic stability. Furthermore, single cell DMFC performance test revealed a power density of 17 mW cm?2 at 30°C and 41 mW cm?2 at 60°C in a 2 M methanol feed. Hence, prepared proton‐conducting bioresource ionomers could have promising potential in the field of green power generation as a low cost and biodegradable polyelectrolyte. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
46.
Molecular dynamics (MD) simulations of structure II clathrate hydrates are performed under canonical (NVT) and isobaric–isothermal
(NPT) ensembles. The guest molecule as a small help gas is xenon and gases such as cyclopropane, isobutane and propane are
used as large hydrocarbon guest molecule (LHGM). The dynamics of structure II clathrate hydrate is considered in two cases:
empty small cages and small cages containing xenon. Therefore, the MD results for structure II clathrate hydrates of LHGM
and LHGM + Xe are obtained to clarify the effects of guest molecules on host lattice structure. To understand the characteristic
configurations of structure II clathrate hydrate the radial distribution functions (RDFs) are calculated for the studied hydrate
system. The obtained results indicate the significance of interactions of the guest molecules on stabilizing the hydrate host
lattice and these results is consistent with most previous experimental and theoretical investigations. 相似文献
47.
Khodabandeh Erfan Akbari Omid Ali Akbari Soheil Taghizadeh Afshin Saffari Pour Mohsen Ersson Mikael Jönsson Pär G. 《Journal of Thermal Analysis and Calorimetry》2021,144(1):245-256
Journal of Thermal Analysis and Calorimetry - In this numerical study, the variations in the surface area of the cooling channels in a solid oxide fuel cell with different cross sections... 相似文献
48.
Acrylamide and N,N′-methylenebis (acrylamide) (AAm-Bis) copolymerization has been investigated in water at a total monomer concentration of the 0.5 M. Conversion of monomer was measured as a function of the reaction time up to the onset of macrogelation. Experimental results indicate that the critical conversion at the gel point shows a minimum at 6 mol.% Bis when the monomer concentration was kept constant at 0.5 M and it was found that polymer formed with different Bis% are not dissolved in water, acetic acid, toluene or chloroform. 相似文献
49.
The influence of surface effects on Frederiks transition in nematic liquid crystal doped with ferroelectric nanoparticles 下载免费PDF全文
Motivated by our recent work,in this work,we present the numerical study of the anchoring effect on the Frederiks threshold field in a nematic liquid crystal doped with ferroelectric colloidal nanoparticles.Assuming weak anchoring conditions,we employ the relaxation method and Maxwell construction to numerically solve the Euler–Lagrangian differential equation for the total free energy together the Rapini–Papoular surface energy to take into account anchoring of nematic liquid crystal molecules at the substrates.In this study,we focus our attention on obtaining the phase diagrams of Frederiks transition for different values of anchoring strength which have been not computed in our previous work.In this way,the effect of nanoparticle radius,nanoparticle volume fraction,nanoparticle polarization,and cell thickness on the Frederiks transition for different values of anchoring conditions are summarized in the phase diagrams.The numerical results show that by increasing the nanoparticles size and nanoparticle volume fraction in the ferronematic system,the Frederiks threshold field is strongly reduced. 相似文献
50.
Fatemeh Sadat Majedi Mohammad Mahdi Hasani‐Sadrabadi Erfan Dashtimoghadam Amir Hossein Haghighi Arnaud Bertsch Homayoun Moaddel Philippe Renaud 《固体物理学:研究快报》2012,6(7):318-320
Interaction between negatively charged Nafion® and a positively charged polybenzimidazole‐decorated carbon nanotube leads to the formation of an ionic complex with high charge density for proton conduction, which can lead to an improvement in transport properties. Here we investigate the high‐temperature and low‐humidity proton conductivity of this nanocomposite membrane as a potential membrane for fuel cell applications.