Thermally stimulated depolarization current behavior of polyethylene/poly(vinyl acetate) blends: Effect of blending

Choure, Churaman; Keller, J. M.; Bajpai, R.

doi:10.1002/app.23849

Cited by 4 publications

(3 citation statements)

References 28 publications

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“…Several reports on TSC behavior of individual polymer thermoelectrets are available 8–10. However, the nature of the various polarization processes and their relative contribution to the electret state of the polymer are not yet fully understood.…”

Section: Introductionmentioning

confidence: 99%

Thermally stimulated depolarization study in polyvinylidenefluoride–polysulfone polyblend films

Saxena

Gaur

2010

J of Applied Polymer Sci

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Thermally stimulated depolarization currents (TSDCs) in short-and open-circuit modes in polyvinylidenefluoride (PVDF)-polysulfone (PSF) polyblend have been recorded. The TSDC thermograms of PVDF and PSF in short-circuit mode show two peaks, whereas the polyblend of the two polymers shows a single peak. With the increase in PSF weight percentage in the polyblend, the magnitude of TSDC peak current increased and the peak current position shifted toward the lower temperature side. The single peak in polyblend appears at 165 C 6 10 C, which is at higher temperature than the temperature of low-temperature peak for individual polymers. This suggests that this peak may be due to dipolar polarization. Subsequently, shifting of peak toward higher temperature side with increase in polarizing temperature indicates the space charge peak. This contradiction has been explained on the basis of induced dipole theory. The behavior of short circuit TSDC could be explained in terms of the heterocharge caused by dipole orientation and ionic homocharge drift, together with the injection of charge car-riers from electrodes and their subsequent localization in surface and bulk traps. However, two oppositely directed TSDC peaks observed in open-circuit mode in all the polyblend samples could be considered as the result of superposition of two overlapped and oppositely directed peaks, one caused by relaxation of dipole polarization and the other by the space charge. Thus, we have compared TSDC measured in open-and short-circuit modes to distinguish between these two relaxation processes and separate them. There is only one broad peak observed in the short-circuit mode of the polyblend, which entirely corresponds to the relaxation of dipole polarization. Insertion of a dielectric gap in the open-circuit mode does not affect the dipole current, but the space charge component flowing in the opposite direction is added to the former.

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Section: Introductionmentioning

confidence: 99%

Thermally stimulated depolarization study in polyvinylidenefluoride–polysulfone polyblend films

Saxena

Gaur

2010

J of Applied Polymer Sci

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“…This blocking is believed to be the cause of motion of the zero-field planes away from the charge injecting electrode, which results in the parting of carrier flow toward the electrode and a net carrier flow away from it, leading to anomalous behavior. 24 The high temperature helps the easy movement of charge carriers in the bulk and leaving less number of space charge on the injecting site. But for the samples which are polarized at low temperatures do not make a smooth movement and thus blocking off the electrode takes place due to the large number of injected charge carriers trapped on the surface of the sample, or in the near-surface region and most trapped charges do not get enough energy to release out from these traps and to become free charge.…”

Section: Resultsmentioning

confidence: 99%

Studies of the effect of temperature on charge accumulation in PVDF-PMMA double-layered thin films based on depolarization current measurements

Saxena

Shukla

2021

Journal of Elastomers & Plastics

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In this paper, we have reported the interpretation of air gap (Thermally Stimulated Depolarization Current) of surface charges in PVDF-PMMA (Polyvinylidene fluoride (PVDF)–Polymethyl methacrylate (PMMA)) double-layered polymer thin films whose decay could not be observed in metalized electrets with short-circuit TSDC. Since short-circuit TSDC is caused by the relaxations of homo- and hetero-charge flow in one direction and thus makes it difficult to identify, separate, and characterize its components, therefore, an air gap was introduced to the short-circuit TSDC technique to carry out air-gap TSDC. This technique enables one to observe the orientation of dipoles, excess charge decay by ohmic conduction, and decay of surface charge. When a dielectric is charged by an application of an external field, two charges with opposite polarity and different nature can be found. Air-gap TSDC’s of double-layer samples revealed the presence of homo charge; charges trapped at the surface are due to dissipation of space charges thus, the depolarization current is observed to have the same polarity as that of the polarization current. Hetero-charge persists at high temperatures due to the bulk polarization formed because of the electric field created by the homo-charge. Hence, the depolarization current observed in the present study was observed to be of opposite polarity as that of polarization current. The above discussed polymeric layered structure was found to be a source of charge trapping which was identified and confirmed by various calculated parameters.

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“…The relaxation occurs in the glassy state of the polymer and is due to the hindered rotation of polar side groups around carbon-carbon link of the main chain. Sometimes and relaxations coalesce to give a single , relaxation around T g as reported in the case of PMMA [16][17][18]. If there are polar side groups in the polymers side chain, capable of orienting in an electric field independent of one another and having different relaxation times, two separate relaxations are observed.…”

Section: Composition Dependencementioning

confidence: 92%

Short Circuit Thermally Stimulated Discharge Current Measurement on PMMA:PEMA:PVDF Ternary Blends

Gupta

Tiwari

Bajpai

et al. 2011

MSA

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The attainment of a better understanding and improvement of electrical properties of ternary blend is a task of particular scientific and economic importance. Ternary films of Poly (methylmethacrylate), Poly (ethlymathacrylate) and poly (vinlylidenefluoride) were prepared using solution cast technique. Thereafter, to study the hetro charges, homo-charges and interfacial charge formation in ternary system, the short circuit thermally stimulated discharge current (SC-TSDC) measurements were carried out on bilaterally metallized electrets. The ternary blend samples taken for the present investigations are hetrogeneous system involving three polymers differing in their conduction behaviour and dielectric property. Thus, unequal ohmic conduction currents arriving at the interface are expected to result in accumulation of charges at the interface or the Maxwell-Wagner effect. Clearly the Maxwell Wagner effect is expected to contribute discernibly to the observed TSDC’s of the ternary blends.The PMMA: PEMA: PVDF:: 100:100:50 blend exhibits highest tendency while 100:50:100 the least, towards the anomalous current flow. Moreover, the conductivity of 100: 100: 50 is found to be more and, therefore, a large amount of homocharge is injected leading to anomalous current

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Thermally stimulated depolarization current behavior of polyethylene/poly(vinyl acetate) blends: Effect of blending

Cited by 4 publications

References 28 publications

Thermally stimulated depolarization study in polyvinylidenefluoride–polysulfone polyblend films

Thermally stimulated depolarization study in polyvinylidenefluoride–polysulfone polyblend films

Studies of the effect of temperature on charge accumulation in PVDF-PMMA double-layered thin films based on depolarization current measurements

Short Circuit Thermally Stimulated Discharge Current Measurement on PMMA:PEMA:PVDF Ternary Blends

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