Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341515
B. Despax, C. Huraux
On a silica surface, polarization current intensity versus time and Thermostimulated Depolarization Current (TDC) spectra were recorded. This polarization depended on the nature of the ambient gas. Higher was the pressure or longer was the exposure time, higher was the polarization current intensity and larger was the TDC peak area. Nevertheless, when the gas pressure in the vessel was enough low during the depolarization, TDC peak temperature jumped to a higher value. According to polarization conditions, specimens could approach to an electret behaviour.
{"title":"Polarization phenomena on a silica surface immersed in various gases","authors":"B. Despax, C. Huraux","doi":"10.1109/ISE.1985.7341515","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341515","url":null,"abstract":"On a silica surface, polarization current intensity versus time and Thermostimulated Depolarization Current (TDC) spectra were recorded. This polarization depended on the nature of the ambient gas. Higher was the pressure or longer was the exposure time, higher was the polarization current intensity and larger was the TDC peak area. Nevertheless, when the gas pressure in the vessel was enough low during the depolarization, TDC peak temperature jumped to a higher value. According to polarization conditions, specimens could approach to an electret behaviour.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"5 1","pages":"404-409"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86514928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341469
H. Frensch, J. Wendorff
The influence of the structure of alloys of semicrystal line poly(vinylidene fluoride) (PVDF) and amorphous poly(methyl methacrylate) (PMMA) on the electret behavior was investigated in detail. The samples were corona charged and subsequently studied by means of the open-circuit thermally-stimulated-current (TSC) technique. In addition, direct current conductivity measurements were performed. The TSC thermograms of the amorphous alloys exhibit a dipole orientation peak at the glass transition, the position of which is sensitive to composition of the blend. A second TSC peak is found to be related to conductivity, presumably ion transport controlled by free volume. A tentative interpretation of the TSC of the semicrystal-line alloys is based on the occurence of Maxwell-Wagner-Sillars charges at the interface between crystalline and amorphous regions.
{"title":"Correlations between the structure and the electret behavior of PVDF/PMMA-alloys","authors":"H. Frensch, J. Wendorff","doi":"10.1109/ISE.1985.7341469","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341469","url":null,"abstract":"The influence of the structure of alloys of semicrystal line poly(vinylidene fluoride) (PVDF) and amorphous poly(methyl methacrylate) (PMMA) on the electret behavior was investigated in detail. The samples were corona charged and subsequently studied by means of the open-circuit thermally-stimulated-current (TSC) technique. In addition, direct current conductivity measurements were performed. The TSC thermograms of the amorphous alloys exhibit a dipole orientation peak at the glass transition, the position of which is sensitive to composition of the blend. A second TSC peak is found to be related to conductivity, presumably ion transport controlled by free volume. A tentative interpretation of the TSC of the semicrystal-line alloys is based on the occurence of Maxwell-Wagner-Sillars charges at the interface between crystalline and amorphous regions.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"15 1","pages":"132-137"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85893131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341464
P. Mehendru, Ramadhar Singh, V. Panwar, N. Gupta
Dielectric measurements have been made on poly (vinyl chloride: vinyl acetate: vinyl alcohol) in the frequency range 30 Hz-100 KHz and in the temperature range 77–410 K. A frequency dependent conductivity described by σ(ω) = A ωs, is observed where S < 1 and is independent of temperature upto 250 K but with further increase in temperature it decreases. Two relaxations, the α-and the β-relaxation, are observed having activation energies ∼ 0.92 and 0.42 eV, respectively. The α-relaxation is attributed to the segmental motion of the main chain consisting of the constituent groups of the terpolymer under dipole-dipole interaction and the β-relaxation is due to the C-C1 dipoles in the amorphous phase of the terpolymer.
{"title":"Hopping transport and relaxation phenomena in poly (vinyl chloride: vinyl acetate: Vinyl alcohol) terpolymer","authors":"P. Mehendru, Ramadhar Singh, V. Panwar, N. Gupta","doi":"10.1109/ISE.1985.7341464","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341464","url":null,"abstract":"Dielectric measurements have been made on poly (vinyl chloride: vinyl acetate: vinyl alcohol) in the frequency range 30 Hz-100 KHz and in the temperature range 77–410 K. A frequency dependent conductivity described by σ(ω) = A ω<sup>s</sup>, is observed where S < 1 and is independent of temperature upto 250 K but with further increase in temperature it decreases. Two relaxations, the α-and the β-relaxation, are observed having activation energies ∼ 0.92 and 0.42 eV, respectively. The α-relaxation is attributed to the segmental motion of the main chain consisting of the constituent groups of the terpolymer under dipole-dipole interaction and the β-relaxation is due to the C-C1 dipoles in the amorphous phase of the terpolymer.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"4 1","pages":"100-105"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87609762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341562
A. J. Bur, S. Roth
The construction, calibration and use of a polyvinylidene fluoride (PVDF) pressure gage is described. The transducer material, PVDF, is in the form of 12 pm films with active areas 1 cm in diameter. The gage consists of two films whose active regions are laminated together face-to-face and subsequently laminated between protective layers of polycarbonate or another suitable polymer material. Temperature compensation, which is achieved by both active and passive techniques, is described. The response of the PVDF gage to shear stresses is found to be significant but small compared to the response to an equivalent hydrostatic pressure.
{"title":"Characterization of polyvinylidene fluoride pressure transducers","authors":"A. J. Bur, S. Roth","doi":"10.1109/ISE.1985.7341562","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341562","url":null,"abstract":"The construction, calibration and use of a polyvinylidene fluoride (PVDF) pressure gage is described. The transducer material, PVDF, is in the form of 12 pm films with active areas 1 cm in diameter. The gage consists of two films whose active regions are laminated together face-to-face and subsequently laminated between protective layers of polycarbonate or another suitable polymer material. Temperature compensation, which is achieved by both active and passive techniques, is described. The response of the PVDF gage to shear stresses is found to be significant but small compared to the response to an equivalent hydrostatic pressure.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"1 1","pages":"712-717"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89587761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341519
J. Lewiner
When an electric field is applied to an insulating material three basic processes can take place: the dipoles tend to rotate, ions migrate and space charge can be injected at the interfaces, depending on such parameters as temperature or applied electric field. For many years, a direct analysis was impossible since the experimentally observable variables gave only an average of what was taking place in the samples under study. Many methods were developed over the years combining available measuring techniques with theoretical hypotheses. They led to phenomenological descriptions but it appeared that a direct measurement of space charge or polarization distributions in the materials would be the way for the understanding of the physical processes involved. In this paper we will present the evolution of these methods and will describe one which seems presently the most promising. It uses the propagation in the sample of a pressure wave which acts as a virtual probe sensitive to charge, field or potential. A very elegant technique to generate this pressure wave involves the use of short-duration laser pulses. It will be shown how this can find applications in a very large number of areas. Examples will be given in such different fields as electrets, high voltage insulation or transducer materials.
{"title":"New experimental techniques","authors":"J. Lewiner","doi":"10.1109/ISE.1985.7341519","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341519","url":null,"abstract":"When an electric field is applied to an insulating material three basic processes can take place: the dipoles tend to rotate, ions migrate and space charge can be injected at the interfaces, depending on such parameters as temperature or applied electric field. For many years, a direct analysis was impossible since the experimentally observable variables gave only an average of what was taking place in the samples under study. Many methods were developed over the years combining available measuring techniques with theoretical hypotheses. They led to phenomenological descriptions but it appeared that a direct measurement of space charge or polarization distributions in the materials would be the way for the understanding of the physical processes involved. In this paper we will present the evolution of these methods and will describe one which seems presently the most promising. It uses the propagation in the sample of a pressure wave which acts as a virtual probe sensitive to charge, field or potential. A very elegant technique to generate this pressure wave involves the use of short-duration laser pulses. It will be shown how this can find applications in a very large number of areas. Examples will be given in such different fields as electrets, high voltage insulation or transducer materials.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"141 6","pages":"429-443"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91422800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341539
G. Sessler, R. Gerhard-Multhaupt, H. von Seggern, J. West
Laser-induced pressure pulses (LIPP's) of < 500 ps duration have been used to measure the ultrasonic attenuation in fluoroethylenepropylene (FEP), polyethyleneterephthalate (PETP) and polyimide (PI) as well as the charge, polarization, and piezoelectricity profiles in the thickness direction of polyvinylidenefluoride (PVDF) and FEP electrets with a resolution of 1 to 2 μm. Measurements on PVDF, obtained during and after poling, reveal a uniform polarization profile for samples poled at room temperature and a non-uniform polarization, concentrated near the positive electrode, for samples poled at elevated temperatures. In FEP, charges injected by electron beams are stored close to the CSDA range while negative carriers deposited by corona discharges or liquid-contact electrodes are trapped at, or close to, the surface.
{"title":"Charge and polarization profiles in polymer electrets","authors":"G. Sessler, R. Gerhard-Multhaupt, H. von Seggern, J. West","doi":"10.1109/ISE.1985.7341539","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341539","url":null,"abstract":"Laser-induced pressure pulses (LIPP's) of < 500 ps duration have been used to measure the ultrasonic attenuation in fluoroethylenepropylene (FEP), polyethyleneterephthalate (PETP) and polyimide (PI) as well as the charge, polarization, and piezoelectricity profiles in the thickness direction of polyvinylidenefluoride (PVDF) and FEP electrets with a resolution of 1 to 2 μm. Measurements on PVDF, obtained during and after poling, reveal a uniform polarization profile for samples poled at room temperature and a non-uniform polarization, concentrated near the positive electrode, for samples poled at elevated temperatures. In FEP, charges injected by electron beams are stored close to the CSDA range while negative carriers deposited by corona discharges or liquid-contact electrodes are trapped at, or close to, the surface.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"19 1","pages":"565-570"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91528738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341542
V. Arkhipov, A. Rudenko, S. Shutov
Radiation-induced conductivity (RIC), storage and relaxation of space charge in disordered dielectrics are theoretically studied under the condition of dispersive transport. Pulsed and step-function regimes of charge-carrier generation are considered for short-circuited samples» It is shown that time dependences of RIG and space charge density (SCD) exhibit some interesting features, which are typical for the dispersive transport. In particular, for the step-function carrier generation RIC passes through a maximum before the steady-state level is established, with the initial asymptote preceding the maximum and the final asymptote following the maximum appeare to be power-law functions of time.
{"title":"Radiation-induced conductivity and charge storage in dielectrics — Dispersive transport regime","authors":"V. Arkhipov, A. Rudenko, S. Shutov","doi":"10.1109/ISE.1985.7341542","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341542","url":null,"abstract":"Radiation-induced conductivity (RIC), storage and relaxation of space charge in disordered dielectrics are theoretically studied under the condition of dispersive transport. Pulsed and step-function regimes of charge-carrier generation are considered for short-circuited samples» It is shown that time dependences of RIG and space charge density (SCD) exhibit some interesting features, which are typical for the dispersive transport. In particular, for the step-function carrier generation RIC passes through a maximum before the steady-state level is established, with the initial asymptote preceding the maximum and the final asymptote following the maximum appeare to be power-law functions of time.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"1 1","pages":"592-956"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90936563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341592
Mireille Laidur, R. L. Moreira
The far infrared spectra of Poly(vinylidene fluoride) and copolymers with trifluorethylene have been measured between 5 and 55 cm−1. In this region of the spectra, the effect of the crystalline phase of the polymer was very small, interference affected the true absorption of the polymer. After correction of this effect, we detected an unpredicted absorption band clearly visible in the β structure of the copolymers.
{"title":"Structural study of poly(vinylidene fluoride) and copolymers by infrared spectroscopy in the millimetre region","authors":"Mireille Laidur, R. L. Moreira","doi":"10.1109/ISE.1985.7341592","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341592","url":null,"abstract":"The far infrared spectra of Poly(vinylidene fluoride) and copolymers with trifluorethylene have been measured between 5 and 55 cm−1. In this region of the spectra, the effect of the crystalline phase of the polymer was very small, interference affected the true absorption of the polymer. After correction of this effect, we detected an unpredicted absorption band clearly visible in the β structure of the copolymers.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"60 1","pages":"900-905"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77748215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341493
Yiqin Zhou, Wei Li, G. Tong, Zongneng Qi, R. Hayakawa
TSC spectra of amorphous and semicrystalline PET annealed at 65 °C and 90 °C for the various duration times have been measured respectively. The drastic effect of sub-Tg on the g amorphous region is observed. The max current of the thermo-relaxation of frozen-in dipoles decreases with increasing of storage time. DSC curves, crystallinity and density of the amorphous specimens were measured. The transition of the amorphous PET from the ductile to brittle fracture appeared at the same storage time as in TSC measurement. It was illustrated that TSC is a sensitive and powerful method for investigating the sub-Tg storage.
{"title":"TSC studies on sub-Tg storage of polymer electret","authors":"Yiqin Zhou, Wei Li, G. Tong, Zongneng Qi, R. Hayakawa","doi":"10.1109/ISE.1985.7341493","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341493","url":null,"abstract":"TSC spectra of amorphous and semicrystalline PET annealed at 65 °C and 90 °C for the various duration times have been measured respectively. The drastic effect of sub-Tg on the g amorphous region is observed. The max current of the thermo-relaxation of frozen-in dipoles decreases with increasing of storage time. DSC curves, crystallinity and density of the amorphous specimens were measured. The transition of the amorphous PET from the ductile to brittle fracture appeared at the same storage time as in TSC measurement. It was illustrated that TSC is a sensitive and powerful method for investigating the sub-Tg storage.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"25 1","pages":"277-282"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79119493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341516
T. Eish, F. Youssef
Experimental investigations on treeing breakdown characteristics of cross-Linked polyethylene (XLPE) cables immersed in transformer oil are introduced and discussed in this paper. The study has been done under alternating (50 Hz) and direct voltage stresses. Thereby, the effect of duration, waveform and polarity of the applied voltage as well as the temperature rise of oil, the size of cable and the diameter of needle electrode on treeing breakdown are included.
{"title":"Factor affecting the treeing breakdown phenomena of XLPE cables","authors":"T. Eish, F. Youssef","doi":"10.1109/ISE.1985.7341516","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341516","url":null,"abstract":"Experimental investigations on treeing breakdown characteristics of cross-Linked polyethylene (XLPE) cables immersed in transformer oil are introduced and discussed in this paper. The study has been done under alternating (50 Hz) and direct voltage stresses. Thereby, the effect of duration, waveform and polarity of the applied voltage as well as the temperature rise of oil, the size of cable and the diameter of needle electrode on treeing breakdown are included.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"79 1","pages":"410-415"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83242033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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