Pressure-temperature study of dielectric relaxation of a polyurethane elastomer

Abstract

The effect of hydrostatic pressure up to 1,361 atms on the dielectric properties of a segmented polyurethane elastomer (Dow 2103‐80AE) is studied at temperatures from 0°C to 80°C. The experimental results show that the relaxation time for both the I–process, associated with the molecular motions in the hard segments, and the α–process, associated with the glass transition, increases with pressure, and this shift is more pronounced for the I–process. Besides the glass transition, it is found that the I–process can be described by the Vogel–Fulcher (V–F) and Williams–Landel–Ferry (WLF) relations. At atmospheric pressure, Tg and T0 for the I–process are 235.9 K and 4.2 × 103 K, respectively. Based on the V–F and WLF relations and experimental results, it is found that a parameter, C1, in the WLF relation is independent of the pressure. Thus, a method is introduced to determine the values of both the characteristic transition temperature (Tg) and activation energy (T0) for the processes at different pressures. As the pressure increases from atmospheric to 1,361 atms, the increase of Tg for the I–process is about 30°C. The results also show that, for both the I– and the α–processes, T0 decreases with increasing pressure. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 983–990, 1999

Structure, phase transition and electric properties of poly(vinylidene fluoride-trifluoroethylene) copolymer studied with density functional theory

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Microfluidic behaviour of perfluoropolyether fluids in poly(dimethylsiloxane) micro-channels

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A Micromachined Capacitive Pressure Sensor Using a Cavity-Less Structure with Bulk-Metal/Elastomer Layers and Its Wireless Telemetry Application

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