Effect of glass transition on conduction current in biodegradable poly-L-lactic acid

Maeno, Y.; Yamaguchi, Yuya; Hirai, Naoshi; Tanaka, Toshikatsu; Ohki, Yoshimichi; Kohtoh, M.; Okabe, Shigemitsu

doi:10.1109/ceidp.2004.1364186

Cited by 10 publications

(7 citation statements)

References 3 publications

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“…As reported in our previous papers [4,7], we measured the relative permittivity of PLLA as a function of temperature, and found that it increased by 0.6 when the temperature crossed T g upward from a lower temperature. It is reasonably assumed that this increase in permittivity is due to the dipoles which became possible to orientate by the glass transition.…”

Section: Resultsmentioning

confidence: 86%

“…In the region higher than 70 °C , the temperature at which the DSC curve shows an endothermic peak associated with the glass transition, the current shows rapid increase with an activation energy of 3.8 eV, which is much higher than the value in the lower temperature region. It was already confirmed that permanent dipoles, mainly consisting of carbonyl groups, become possible to rotate around this temperature [4]. Due to these reasons, PLLA has a relatively high conductivity at high temperatures in spite of its low conductivity comparable to LDPE at room temperature.…”

Section: Resultsmentioning

confidence: 89%

“…(4) In PLLA, displacement current caused by the dipolar orientation of additives, flows at temperatures above about 80 °C . (5) In PETS, TSDC, which is far larger than the one caused by orientational depolarization around T g , flows above 80 °C .…”

Section: Resultsmentioning

confidence: 99%

“…However, their applicability to the electrical insulation field has not been clarified yet. Among many biodegradable polymers, only PLLA has been examined on some dielectric properties [1][2][3][4][5]. However, there has been almost no research that compares dielectric properties of different biodegradable polymers systematically.…”

Section: Introductionmentioning

confidence: 99%

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Electrical Conduction and Breakdown Properties of Several Biodegradable Polymers

Ohki

Hirai

2007

IEEE Trans. Dielect. Electr. Insul.

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In order to respond to soaring public concern about environmental protection, various biodegradable polymers have been developed. The present paper reports the electrical conduction and breakdown properties of various biodegradable polymers such as poly-L-lactic acid (PLLA), polyethylene terephthalate succinate (PETS), polycaprolactone butylene succinate (PCL-BS), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), and polyhydroxybutyrate/valerate (PHB/V) in comparison to those of low-density polyethylene (LDPE). While the permittivity and conductivity of PLLA and PETS are comparable to LDPE, those of PCL-BS and PBS are much higher. The conductivity is also higher in PBSA. This is because PLLA and PETS are in the glass state at room temperature, while PCL-BS, PBS, and PBSA are in the rubber state. Furthermore, PLLA and PETS show a strong temperature dependence of the conductivity, which is divided into two or three regions, and they also show thermally stimulated polarization or depolarization current around their respective glass transition temperatures. In contrast to the large difference in conductivity among different kinds of samples, all the polymers tested have almost similar impulse breakdown strength at room temperature. As for dc or ac breakdown strength, PLLA and PETS show a relatively higher strength than PCL-BS and PBS.

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electrical Conduction and Breakdown Properties of Several Biodegradable Polymers

Ohki

Hirai

2007

IEEE Trans. Dielect. Electr. Insul.

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“…The basic electrical insulation properties such as volume resistivity, dielectric constant, dielectric loss tangent, space charge accumulation, conduction current, and resistance to ultraviolet photons of polylactic acid (PLA) at room temperature have been measured and compared with the present insulating materials including cross-linked PE (XLPE), PE, and polypropylene [10][11][12][13][14]. The basic electrical insulation properties such as volume resistivity, dielectric constant, dielectric loss tangent, space charge accumulation, conduction current, and resistance to ultraviolet photons of polylactic acid (PLA) at room temperature have been measured and compared with the present insulating materials including cross-linked PE (XLPE), PE, and polypropylene [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Pattern analysis on dielectric breakdown characteristics of biodegradable polyethylene film under nonuniform electric field

Liu

2011

Int. Trans. Electr. Energ. Syst.

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SUMMARY This article presents pattern analysis to identify the dielectric breakdown characteristics of biodegradable polyethylene film under nonuniform electric field affected by the contaminated conditions, with low‐density polyethylene (LDPE) film as the reference. When the specimens were immersed in the electrolyte for different periods, their degradation was observed and the breakdown experiments were carried out by the needle‐plane electrode pattern with the air gap of 10 mm. The breakdown voltage was measured to determine the discharge and breakdown mechanism in the air/film gap under the nonuniform electric field. Meanwhile, the breakdown phenomena were captured by a monocular‐video‐zoom microscope, and the related breakdown characteristics were quantitatively analyzed through the methods of image processing and fractal dimension to establish the relationship between the pattern characteristics of breakdown craters and the dielectric properties. It is found that the morphology of breakdown region and the distribution of discharge profile in relationship with the contaminated levels can provide an optical evaluation method for the insulating materials. Compared with LDPE, biodegradable polyethylene shows the better breakdown endurance. By increasing the electrolyte conductivity and the immersion time, the breakdown voltage, the breakdown area, and the box dimension of the breakdown crater decrease. The breakdown voltage is higher than that of LDPE, whereas the breakdown area and the box dimension are lower. The results obtained indicate that the image–pattern identification technique is fairly well to quantify the breakdown phenomena of polymer films. Both breakdown area and box dimension reasonably give a scale to identify the dielectric properties for further investigation on feasibility of using biodegradable polymers. Copyright © 2011 John Wiley & Sons, Ltd.

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Temperature effects on electric charge transport processes and electron emission in PBS–clay nanocomposites submitted to electron bombardment

Taktak

Fakhfakh

Rondot

et al. 2023

J. Phys. D: Appl. Phys.

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Isothermal conditions effects on the charge transport processes and electron emission properties in polybutylene succinate (PBS) nanoclay composites are investigated. The temperature range used (20°C to 80°C) is close to the conditions of use of materials in many applications (insulation, sensors). These effects are highlighted using an appropriate device, placed in a scanning electron microscope (SEM), allowing measurement of induced currents in an electron irradiated specimen. The experimental results showed that the rise in temperature involves a decrease in the charging ability and an increase in conductivity of PBS nanocomposites. The mobility of charge carriers and its thermal dependency deduced during the discharge step were found to be lower for the nanocomposites. A qualitative analysis, expressed for understanding these observations, is based on the determination of electron trap energy distribution (i.e. density of occupied states). Secondary electron emission yield decreased with increasing temperature. The results help us envision a new class of insulators with improved electrical performances. The operating thermal stress, combined with the absence of trapped charges, allows to reduce the electrical and thermal aging and to ensure consequently the long-term reliability of the insulators (for instance under HV).

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Effect of glass transition on conduction current in biodegradable poly-L-lactic acid

Cited by 10 publications

References 3 publications

Electrical Conduction and Breakdown Properties of Several Biodegradable Polymers

Electrical Conduction and Breakdown Properties of Several Biodegradable Polymers

Pattern analysis on dielectric breakdown characteristics of biodegradable polyethylene film under nonuniform electric field

Temperature effects on electric charge transport processes and electron emission in PBS–clay nanocomposites submitted to electron bombardment

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