Lanca, M. C., S. Peuckert, E. R. Neagu, L. Gil, P. C. Silva, and J. Marat-Mendes. "
Electrical Properties Studies of a Cork/TetraPak (R)/Paraffin Wax Composite."
Advanced Materials Forum Iv. Eds. AT Marques, AF Silva, APM Baptista, C. Sa, FJLA Alves, LF Malheiros, and M. Vieira. Vol. 587-588. Materials Science Forum, 587-588. 2008. 613-617.
AbstractLately the electrical and dielectric properties of cork and some cork-based materials (commercial and non-commercial) have been studied in order to understand their ability to store electrical charge. The main problem found so far is related to the water content in cork, only of a few % weight. but large enough to influence greatly the conductivity of cork and, consequently, the charge storage capability. To overcome this problem cork has been combined with hydrophobic materials. In this work a commercial wax (paraffin wax) was used to produce a cork/paraffin composite by hot pressing. After milled and mixed natural cork. TetraPak (R) containers waste and paraffin were pressed to make plaques of a new composite. Different concentrations of cork. TetraPak (R) and paraffin, different granules sire, different temperature and pressure were used to produce the samples. The electrical properties of the new composite were measured by the isothermal charging and discharging current method and the results compared to previously ones obtained for natural cork and other derivative products. The new composite has shown to have lower conductivity than the commercial agglomerate. which makes it a better material for charge storage.
Lanca, M. C., S. Peuckert, E. R. Neagu, L. Gil, P. C. Silva, and J. Marat-Mendes. "
Electrical Properties Studies of a Cork/TetraPak (R)/Paraffin Wax Composite."
Advanced Materials Forum Iv. 587-588 (2008): 613-617.
AbstractLately the electrical and dielectric properties of cork and some cork-based materials (commercial and non-commercial) have been studied in order to understand their ability to store electrical charge. The main problem found so far is related to the water content in cork, only of a few % weight. but large enough to influence greatly the conductivity of cork and, consequently, the charge storage capability. To overcome this problem cork has been combined with hydrophobic materials. In this work a commercial wax (paraffin wax) was used to produce a cork/paraffin composite by hot pressing. After milled and mixed natural cork. TetraPak (R) containers waste and paraffin were pressed to make plaques of a new composite. Different concentrations of cork. TetraPak (R) and paraffin, different granules sire, different temperature and pressure were used to produce the samples. The electrical properties of the new composite were measured by the isothermal charging and discharging current method and the results compared to previously ones obtained for natural cork and other derivative products. The new composite has shown to have lower conductivity than the commercial agglomerate. which makes it a better material for charge storage.
Lanca, Carmo M., Stefan Peuckert, Eugen R. Neagu, Luis Gil, Paulo C. Silva, and Jose Marat-Mendes. "
Electrical Properties Studies of a Cork/TetraPak (R)/Paraffin Wax Composite."
Advanced Materials Forum Iv. Eds. AT Marques, AF Silva, APM Baptista, C. Sa, FJLA Alves, LF Malheiros, and M. Vieira. Vol. 587-588. Materials Science Forum, 587-588. 2008. 613-617.
AbstractLately the electrical and dielectric properties of cork and some cork-based materials (commercial and non-commercial) have been studied in order to understand their ability to store electrical charge. The main problem found so far is related to the water content in cork, only of a few % weight. but large enough to influence greatly the conductivity of cork and, consequently, the charge storage capability. To overcome this problem cork has been combined with hydrophobic materials. In this work a commercial wax (paraffin wax) was used to produce a cork/paraffin composite by hot pressing. After milled and mixed natural cork. TetraPak (R) containers waste and paraffin were pressed to make plaques of a new composite. Different concentrations of cork. TetraPak (R) and paraffin, different granules sire, different temperature and pressure were used to produce the samples. The electrical properties of the new composite were measured by the isothermal charging and discharging current method and the results compared to previously ones obtained for natural cork and other derivative products. The new composite has shown to have lower conductivity than the commercial agglomerate. which makes it a better material for charge storage.
Lanca, Carmo M., Stefan Peuckert, Eugen R. Neagu, Luis Gil, Paulo C. Silva, Jose Marat-Mendes, AT Marques, AF Silva, APM Baptista, C. Sa, FJLA Alves, LF Malheiros, and M. Vieira. "
Electrical Properties Studies of a Cork/TetraPak (R)/Paraffin Wax Composite."
Advanced Materials Forum Iv. Vol. 587-588. 2008. 613-617.
Abstractn/a
Neagu, R. M., E. R. Neagu, M. C. Lanca, and J. N. Marat-Mendes. "
New Experimental Facts Concerning the Thermally Stimulated Discharge Current in Dielectric Materials."
Advanced Materials Forum Iv. Eds. AT Marques, AF Silva, APM Baptista, C. Sa, FJLA Alves, LF Malheiros, and M. Vieira. Vol. 587-588. Materials Science Forum, 587-588. 2008. 328-332.
AbstractThe thermally stimulated discharge current (TSDC.) method is a very sensitive and a very selective technique to analyze dipole disorientation and the movement of de-trapped space charge (SC). We have proposed a variant of the TSDC method, namely the final thermally stimulated discharge current (FTSDC) technique. flee experimental conditions can be selected so that the FTSDC is mainly determined by the SC de-trapping. The temperatures of the maximum intensity of the fractional polarization peaks obtained at low temperature, in the range of the local (secondary) relaxation, are in general about 10 to 20 K above the poling temperature. Measurements of the FTSDC in a wide temperature range demonstrate the existence of an apparent peak at a temperature T-ma shifted with about 10 to 30 K above the charging temperature T-c. The shift of T-ma with respect to T-c depends on the experimental conditions. The peak width at the half maximum intensity decreases as T-c increases and the thermal apparent activation energy increases. The variations are not monotonous revealing the temperature range where the molecular motion is stronger and consequently the charge trapping and de-trapping processes are affected. Our results demonstrate that there is a strong similarity between the elementary peaks obtained by the two methods, and the current is mainly determined by SC de-trapping. Even the best elementary peaks are not fitted very well by the analytical equation, indicating that the hypothesis behind this equation have to be reconsidered.