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High - performance hybrid magnetorheological materials / W. Zhang in Industrial & engineering chemistry research, Vol. 49 N° 24 (Décembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp12471–12476 Titre : High - performance hybrid magnetorheological materials : preparation and mechanical properties Type de document : texte imprimé Auteurs : W. Zhang, Auteur ; X. L. Gong, Auteur ; S. H. Xuan, Auteur Année de publication : 2011 Article en page(s) : pp12471–12476 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Magnetorheological  Mechanical  properties Résumé : To improve mechanical performance of magnetorheological elastomers (MREs), two novel hybrid magnetorheological elastomers that were embedded with magnetorheological fluids (MRFs) and magnetorheological gels (MRGs) were fabricated. In this work, MRFs and MRGs were injected into different numbers of holes that were punched on MRE specimens regularly. The nonlinear mechanical properties of the as-prepared magnetorheological fluid-elastomers (MRFEs) and magnetorheological gel-elastomers (MRGEs) were investigated in the presence of external homogeneous magnetic fields. The modulus, loss factor, and hysteresis were evaluated with a modified dynamic mechanical analyzer (DMA) and vibrating sample magnetometer (VSM). Dependence of the rheological response on the volume fraction was also investigated. As the experimental results show, not only were the initial moduli of the two novel hybrid magnetorheological materials higher than those of both the MRFs and MRGs, but also their magnetorheological (MR) effects were better than those of MREs. The loss factors of the two new hybrids were different from those of traditional MREs. Moreover, their dynamic properties changed according to the different volume ratios of MRFs and MRGs injected into the MRE specimens. These results suggest that the two novel hybrid magnetorheological elastomers are improved systems with volume-fraction-dependent rheological responses and the mechanical properties of MREs can be improved by embedding them with MRFs and MRGs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101904f [article] High - performance hybrid magnetorheological materials : preparation and mechanical properties [texte imprimé] / W. Zhang, Auteur ; X. L. Gong, Auteur ; S. H. Xuan, Auteur . - 2011 . - pp12471–12476. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 24 (Décembre 2010) . - pp12471–12476 Mots-clés : Magnetorheological  Mechanical  properties Résumé : To improve mechanical performance of magnetorheological elastomers (MREs), two novel hybrid magnetorheological elastomers that were embedded with magnetorheological fluids (MRFs) and magnetorheological gels (MRGs) were fabricated. In this work, MRFs and MRGs were injected into different numbers of holes that were punched on MRE specimens regularly. The nonlinear mechanical properties of the as-prepared magnetorheological fluid-elastomers (MRFEs) and magnetorheological gel-elastomers (MRGEs) were investigated in the presence of external homogeneous magnetic fields. The modulus, loss factor, and hysteresis were evaluated with a modified dynamic mechanical analyzer (DMA) and vibrating sample magnetometer (VSM). Dependence of the rheological response on the volume fraction was also investigated. As the experimental results show, not only were the initial moduli of the two novel hybrid magnetorheological materials higher than those of both the MRFs and MRGs, but also their magnetorheological (MR) effects were better than those of MREs. The loss factors of the two new hybrids were different from those of traditional MREs. Moreover, their dynamic properties changed according to the different volume ratios of MRFs and MRGs injected into the MRE specimens. These results suggest that the two novel hybrid magnetorheological elastomers are improved systems with volume-fraction-dependent rheological responses and the mechanical properties of MREs can be improved by embedding them with MRFs and MRGs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101904f

Synthesis of imidazoline-based dissymmetric bis-quaternary ammonium gemini surfactant and its inhibition mechanism on Q235 steel in hydrochloric acid medium / J. Zhang in Materials and corrosion, Vol. 63 N° 7 (Juillet 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 7 (Juillet 2012) . - pp. 636–645 Titre : Synthesis of imidazoline-based dissymmetric bis-quaternary ammonium gemini surfactant and its inhibition mechanism on Q235 steel in hydrochloric acid medium Type de document : texte imprimé Auteurs : J. Zhang, Auteur ; X. L. Gong, Auteur ; W.-W. Song, Auteur Année de publication : 2012 Article en page(s) : pp. 636–645 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Acid  inhibition;  adsorption;  dissymmetric  bisquaternary  ammonium  salt;  imidazoline  inhabitor;  quantum  chemical  calculations Résumé : An imidazoline-based dissymmetric bis-quaternary ammonium gemini surfactant has been synthesized. Its surface active properties at equilibrium in water at 25 °C were determined. The inhibitive effect of the compound on Q235 steel in 1 M hydrochloric solution was investigated by the weight-loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) analysis, and quantum chemical calculations. The results indicate that the compound has high surface properties and the inhibition efficiency (IE) increases with the increase in inhibitor concentration, which attain the maximum value around the CMC value. The imidazoline-based dissymmetric bis-quaternary ammonium acts as a mixed type inhibitor mainly inhibiting the cathodic processes and does not change the mechanism of either hydrogen evolution reaction or mild steel dissolution. The best IE is obtained at the immersion time of 144 h. The adsorption of the studied inhibitor on Q235 steel can be fitted to a Langmuir isotherm and the adsorption process is a spontaneous chemical adsorption. Quantum chemistry calculation results show that the imidazoline ring and heteroatoms of N, O, are the active sites of the inhibitors. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201006051/abstract [article] Synthesis of imidazoline-based dissymmetric bis-quaternary ammonium gemini surfactant and its inhibition mechanism on Q235 steel in hydrochloric acid medium [texte imprimé] / J. Zhang, Auteur ; X. L. Gong, Auteur ; W.-W. Song, Auteur . - 2012 . - pp. 636–645. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 7 (Juillet 2012) . - pp. 636–645 Mots-clés : Acid  inhibition;  adsorption;  dissymmetric  bisquaternary  ammonium  salt;  imidazoline  inhabitor;  quantum  chemical  calculations Résumé : An imidazoline-based dissymmetric bis-quaternary ammonium gemini surfactant has been synthesized. Its surface active properties at equilibrium in water at 25 °C were determined. The inhibitive effect of the compound on Q235 steel in 1 M hydrochloric solution was investigated by the weight-loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) analysis, and quantum chemical calculations. The results indicate that the compound has high surface properties and the inhibition efficiency (IE) increases with the increase in inhibitor concentration, which attain the maximum value around the CMC value. The imidazoline-based dissymmetric bis-quaternary ammonium acts as a mixed type inhibitor mainly inhibiting the cathodic processes and does not change the mechanism of either hydrogen evolution reaction or mild steel dissolution. The best IE is obtained at the immersion time of 144 h. The adsorption of the studied inhibitor on Q235 steel can be fitted to a Langmuir isotherm and the adsorption process is a spontaneous chemical adsorption. Quantum chemistry calculation results show that the imidazoline ring and heteroatoms of N, O, are the active sites of the inhibitors. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201006051/abstract