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|Title:||Temperature and frequency dependent dielectric constant/loss studies in pristine and high temperature annealed poly (p-phenylene sulphide)|
|Authors:||Quamara, J K|
|Abstract:||Temperature and frequency dependent dielectric behaviour has been investigated for pristine and high temperature annealed poly p-phenylene sulphide (PPS) in the temperature range 30 to 250 °C at frequencies 120 Hz,1, 10 and 100 kHz. Samples used were in the form of pellets. A continuous decrease in dielectric constant from 30 to 140 °C is according to Kirkwood model. A dipolar relaxation process (β'-relaxation) associated with the newly formed cross-linked structure due to annealing and rigid amorphous phase (RAP) dipolar relaxation (δ-relaxation) have been held responsible to dominate the dielectric behaviour in the temperature region 140 to 190 °C and making ε' temperature independent in this temperature region. A dielectric loss maxima observed between 140 to 160 °C confirms β'-relaxation. Above 190 °C, the crystalline amorphous region with RAP as interface material leading to interfacial polarization (α-relaxation) has been held responsible for increasing the ε' value with temperature. The α-relaxation is confirmed through a dielectric loss peak in ε"-T curve around 230 °C. The frequency dependent nature of the α-loss peak shows its distributive nature in relaxation time. A decrease in the α- and β'-loss peak magnitudes in high temperature annealed samples is due to increase in crystallinity.|
|ISSN:||0975-1041 (Online); 0019-5596 (Print)|
|Appears in Collections:||IJPAP Vol.40(06) [June 2002]|
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