Thermal activation currents of biocompatible nanocrystalline calcium hydroxyapatite Ca10(PO4)6(OH)2

Abstract

Nanocrystalline stoiochiometric calcium hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2 (NCHA), a counter part of the inorganic osseous tissue component, is synthesized under biomimetic conditions. Methods of physico chemical analysis (XRD, IRS, derivatography, DSC, ESCA, SEM, TEM) are used to identify the products of synthesis. The temperature dependence of thermally stimulated currents (TSCs) of NCHA is studied in the temperature range of 300-600 K and the effect of the dispersion degree on TSCs is analyzed.

The influence of methylcellulose (MC) on solubility of calcium hydroxyapatite (HA) crystals in HA/MC nanocomposites

“…The GA/MC OMC weight loss curve (5 wt %) (Fig. 7b) becomes shallow with insufficient heat effect at 72°C, which is apparently due to the losses of adsorbed water in the sample and is quite similar to the thermal curves of the individual stoichiometric GA NC [15]. It is worth mentioning that no effects related to the MC decomposition in the OMC manifested themselves in the GA/MC OMC thermal decomposition curves (Fig.…”

“…The similar phenomenon arises in the agglomeration of GA NCs in the GA based composites and multi walled carbon nanotubes (CNTs) [49]. Nevertheless, in contradistinction to GA/MC OMCs, the GA/CNT composites are subjected to a decrease in the length of the prismatic GA NCs in agglomerates with growing CNT content in the composite.…”

“…According to data on the studied exoelectron emission in GA crystals [43][44][45][46][47][48], the GA emission peaks are observed at a temperature of about 220°C. The GA thermostimu lated depolarization current peak [49][50][51] and anom alies of the dielectric characteristics (dielectric perme ability and dielectric loss tangent) [52][53][54] that are attributed to reorientation of the dipole ОНgroups of GA and, respectively, to redistribution of the charges in GA NC mesocrystals also correspond to this tem perature range.…”