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P, J., L. MC, M. - M. S. J, and R. J, "Pore dimension of water trees in PE: NMR studies", POLYMER, vol. 41: Univ Paris 11, Univ Nova Lisboa, Univ Paris 11, Univ Paris 11, pp. 8151-8154, Jan, 2000. Abstract
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Pedrosa, A., M. C. Lanca, J. P. Borges, E. R. Neagu, C. J. Dias, J. N. Marat-Mendes, and Ieee, "Influence of Polarization on the Bioactivity of Nanopowders of Hydroxyapatite", 2011 14th International Symposium on Electrets (Ise), pp. 55-56, 2011. Abstract
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Pedrosa, A., M. C. Lanca, J. P. Borges, E. R. Neagu, C. J. Dias, J. N. Marat-Mendes, and Ieee, Influence of Polarization on the Bioactivity of Nanopowders of Hydroxyapatite, , pp. 55-56, 2011. AbstractWebsite
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Prezas, P. R., B. M. G. Melo, L. C. Costa, M. A. Valente, M. C. Lança, J. M. G. Ventura, L. F. V. Pinto, and M. P. F. Graça, "TSDC and impedance spectroscopy measurements on hydroxyapatite, β-tricalcium phosphate and hydroxyapatite/β-tricalcium phosphate biphasic bioceramics", Applied Surface Science, vol. 424, issue 1, pp. 28-38, 2017. Abstract

Bone grafting and surgical interventions related with orthopaedic disorders consist in a big business, generating large revenues worldwide every year. There is a need to replace the biomaterials that currently still dominate this market, i.e., autografts and allografts, due to their disadvantages, such as limited availability, need for additional surgeries and diseases transmission possibilities. The most promising replacement materials are biomaterials with bioactive properties, such as the calcium phosphate-based bioceramics group. The bioactivity of these materials, i.e., the rate at which they promote the growth and directly bond with the new host biological bone, can be enhanced through their electrical polarization.In the present work, the electrical polarization features of pure hydroxyapatite (Hap), pure β-tricalcium phosphate (β-TCP) and biphasic hydroxyapatite/β-tricalcium phosphate composites (HTCP) were analyzed by measuring thermally stimulated depolarization currents (TSDC). The samples were thermoelectrically polarized at 500. °C under a DC electric field with a magnitude of 5. kV/cm. The biphasic samples were also polarized under electric fields with different magnitudes: 2, 3, 4 and 5. kV/cm. Additionally, the depolarization processes detected in the TSDC measurements were correlated with dielectric relaxation processes observed in impedance spectroscopy (IS) measurements.The results indicate that the β-TCP crystalline phase has a considerable higher ability to store electrical charge compared with the Hap phase. This indicates that it has a suitable composition and structure for ionic conduction and establishment of a large electric charge density, providing great potential for orthopaedic applications.