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|Title:||Ionic conduction and dielectric dispersion study on chain dynamics of poly(vinyl pyrrolidone)–glycerol blends|
|Authors:||Sengwa, R J|
|Keywords:||Poly(vinyl pyrrolidone)-glycerol blends;Chain dynamics;Dielectric constant;Dielectric relaxation time;Electrical conductivity|
|Abstract:||Dielectric behaviour of glass-former polymer blends i.e. poly(vinyl pyrrolidone) (PVP) (average molecular weight Mw= 24000, 40000 and 360000 g mol-1) with glycerol (Gly) up to 30 wt % PVP has been investigated in the frequency range 20 Hz-1 MHz at 25ºC. The frequency dependent complex dielectric constant of the PVP-Gly blends indicates the relaxation process caused by the micro-Brownian chain motion of the PVP in the frequency range 10 kHz-1 MHz. The values of dielectric relaxation strength and relaxation time for this process were determined to explore the concentration and chain length effect on the relaxation process. The ac conductivity values were found corresponding to dc conductivity at frequencies lower than 10 kHz. The loss part of electric modulus exhibits a peak in the frequency range 10 kHz - 40 kHz, which corresponds to the ionic conductivity relaxation. The complex impedance plane plots of PVP-Gly blends confirm the contribution of the electrode surface polarization effect on the dielectric constant values at frequencies lower than 200 Hz. Further, the results of the dielectric dispersion of the PVP–Gly blends were compared with the dielectric dispersion of poly(vinyl pyrrolidone)–ethylene glycol oligomers (PVP–EGOs) blends [Shinyashiki et al., 2006] to confirm the effect of number of hydroxyl groups of the solvent molecules on the heterogeneous hydrogen bond complex formation in these blends.|
|Appears in Collections:||IJPAP Vol.46(07) [July 2008]|
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