Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5190654 | Polymer | 2006 | 10 Pages |
Abstract
The measurements of ac conductivity [Ïm(Ï)], dielectric constant [Éâ²(Ï)] and loss [Éâ³(Ï)] have been performed on solution grown (thickness â¼85 μm) and uniaxially stretched (thickness â¼25, 45 and 80 μm) films of poly(vinylidene fluoride) (PVDF) in the frequency range 0.1 kHz-10 MHz and in the temperature range 77-400 K. The Ïm(Ï) can be described by the relation Ï(Ï) = AÏs, where s is close to unity and decreases with increase in temperature. Three relaxations, observed in the present investigation, have been designated as the αc-, the αa- and the β-relaxations appearing from high temperature side to the low temperature side. The αc-relaxation could not be observed in the case of uniaxially stretched poly(vinylidene fluoride) films. The αc- and αa-relaxations are associated with the molecular motions in the crystalline regions and micro-Brownian motion in the amorphous regions of the main polymer chain, respectively, whereas the β-relaxation is attributed to the rotation of side group dipoles or to the local oscillations of the frozen main polymer chain.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Ramadhar Singh, Jitendra Kumar, Rajiv K. Singh, Amarjeet Kaur, R.D.P. Sinha, N.P. Gupta,