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Your search keyword '"Qazvini, Nader Taheri"' showing total 2 results
Start Over Author "Qazvini, Nader Taheri" Topic polymethylmethacrylate
2 results on '"Qazvini, Nader Taheri"'

1. Partial Restoring of Thermorheological Simplicity and Terminal Dynamics Behavior of PEO/PMMA in the Presence of Nanoparticles.

Author

Ghelichi, Mahdi, Qazvini, Nader Taheri, Jafari, Seyed Hassan, and Khonakdar, Hossein Ali

Subjects
*THERMAL properties of polymers, *RHEOLOGY, *POLYMETHYLMETHACRYLATE, *NANOPARTICLES, *MISCIBILITY, *MONTMORILLONITE, *MOLECULAR dynamics, *POLYETHYLENE oxide, *TEMPERATURE effect, *SUPERPOSITION principle (Physics)
Abstract

The influence of nanoparticles on the terminal dynamics and thermorheology of miscible PEO/PMMA is studied through rheology. It is found that the dynamics of the components would be highly altered in the presence of nanoparticles, sodium montmorillonite. The dynamics of PEO is retarded due to its absorbance to the surface of the nanoparticles. However, the dynamics of PMMA is seen to be accelerated because of the compatibilizing effect of nanoparticles via introducing favorable interactions. Failure of time-temperature superposition (TTS) was apparent in the case of neat blend, whereas addition of nanoparticles resulted in partial restoring the TTS. [ABSTRACT FROM AUTHOR]

Published
2011
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2. Conformational, thermal, and ionic conductivity behavior of PEO in PEO/PMMA miscible blend: Investigating the effect of lithium salt.

Author

Ghelichi, Mahdi, Qazvini, Nader Taheri, Jafari, Seyed Hassan, Khonakdar, Hossein Ali, Farajollahi, Yaser, and Scheffler, Christina

Subjects
CONFORMATIONAL analysis, THERMAL conductivity, IONIC conductivity, POLYETHYLENE oxide, POLYMETHYLMETHACRYLATE, CRYSTALLIZATION, DIFFERENTIAL scanning calorimetry
Abstract

In this research, influence of incorporating LiClO4 salt on the crystallization, conformation, and ionic conductivity of poly(ethylene oxide) (PEO) in its miscible blend with poly(methyl methacrylate) (PMMA) is studied. Differential scanning calorimetry showed that the incorporation of salt ions into the blend suppresses the crystallinity of PEO. The X-ray diffraction revealed that the unit-cell parameters of the crystals are independent of the LiClO4 concentration despite of the existence of ionic interactions between PEO and Li cations. In addition, the complexation of the Li+ ions by oxygen atoms of PEO is investigated via Fourier transform infrared spectroscopy. The conformational changes of PEO segments in the presence of salt ions are studied via Raman spectroscopy. It is found that PEO chains in the blend possess a crown-ether like conformation because of their particular complexation with the Li+ ions. This coordination of PEO with lithium cations amorphize the PEO and is accounted for suppressed crystallinity of PEO in the presence of salt ions. Finally, electrochemical impedance spectroscopy is used to characterize the ionic conductivity of PEO in the PEO/PMMA/LiClO4 ternary mixture at various temperatures. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Published
2013
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