Showing 2 results for A. Nemati
J. Jaafaripour Maybody, E. Salahi, A. Nemati, M.h. Amin,
Volume 30, Issue 1 (Jun 2011)
Abstract
In the present study, in-situ synthesis of carbon nanotube/hydroxyapatite nano composite powder with stable homogeneous dispersions of carbon nanotubes (CNTs) was carried out using surfactant as dispersing agent. By applying sol-gel method, dispersion in the hydroxyapatite matrix and its effects on the microstructure were investigated. The chemical and phase composition, structure and morphological and size analyses were performed using XRD, FT-IR, SEM, TEM/SAED/EDX, Raman, UV-Vis spectroscopy and differential scanning calorimetry (DSC). The influences of different dispersing agents (sodium dodecyl sulfate, SDS) as a benchmark for future dispersion experiments) and excitation wavelength are discussed and the results are compared to the commonly used UV-Visible spectroscopic analysis. The results indicated that synthesis of hydroxyapatite particles in the presence of the carbon nanotubes had the best homogenization of the carbon nanotube dispersion and faster crystallization of hydroxyapatite, and the use of SDS for dispersion carbon nanotubes at hydroxyapatite matrix rendered formation of hydroxyapatite coating on CNTs surface. The average crystallite size of heat-treated (at 600°C) samples, estimated by Scherrer,s equation, was found to be ~50-60 nm that was confirmed by TEM.
Z. Taherian, M. A. Yousefpour, M. A. Faghihi Sani, A. Nemati,
Volume 31, Issue 1 (Jun 2012)
Abstract
The aim of this work was synthesis of MCM-41/HA nanocomposite and biodegradation behavior of pure silica-mesoporous in attendance of hydroxyapatite crystals. These materials were synthsized by sol-gel method and ageing at 100°C for 24hr. A surfactant was used as template. The pores were formed after removal of surfactant by calcination at 550°C. FTIR results demonstrated formation of silanol and siloxan groups of silica network and hydroxyl and phosphate groups of HA network. Also SEM, TEM and EDS results confirmed presence of HA crystals within MCM-41 structure. Finally biodegradation behavior was examined by ICP and FTIR analysis. The results indicated biodegradable HA phase in the nanocomposite (with release of Ca2+ inos in water and the increasing of the pH value) can increase non-bridging oxygens of the silica network and therefore, it improves biodegradation behavior of silica network.
