Synthesis of silica cryogel-glass fiber blanket by vacuum drying

none3Kunjalukkal Padmanabhan, Sanosh; Ul Haq, Ehsan; Licciulli, AntonioKUNJALUKKAL PADMANABHAN, Sanosh; UL HAQ, Ehsan; Licciulli, ANTONIO ALESSANDR

Setting and curing of mortars obtained by alkali activation and inorganic polymerization from sodium silicate and silica aggregate

none4Haq, Ehsan Ul; Kunjalukkal Padmanabhan, Sanosh; Abdul Karim, Muhammad Ramzan; Licciulli, AntonioHaq, Ehsan Ul; KUNJALUKKAL PADMANABHAN, Sanosh; Abdul Karim, Muhammad Ramzan; Licciulli, ANTONIO ALESSANDR

Hydroxy propyl cellulose capped silver nanoparticles produced by simple dialysis process

Silver (Ag) nanoparticles (∼6 nm) were synthesized using a novel dialysis process. Silver nitrate was used as a starting precursor, ethylene glycol as solvent and hydroxy propyl cellulose (HPC) introduced as a capping agent. Different batches of reaction mixtures were prepared with different concentrations of silver nitrate (AgNO3). After the reduction and aging, these solutions were subjected to ultra-violet visible spectroscopy (UVS). Optimized solution, containing 250 mg AgNO3 revealed strong plasmon resonance peak at ∼410 nm in the spectrum indicating good colloidal state of Ag nanoparticles in the diluted solution. The optimized solution was subjected to dialysis process to remove any unreacted solvent. UVS of the optimized solution after dialysis showed the plasmon resonance peak shifting to ∼440 nm indicating the reduction of Ag ions into zero-valent Ag. This solutionwas dried at 80 8C and the resultant HPC capped Ag (HPC/Ag) nanoparticles were studied using transmission electron microscopy (TEM) for their particle size and morphology. The particle size distribution (PSD) analysis of these nanoparticles showed skewed distribution plot with particle size ranging from 3 to 18 nm. The nanoparticles were characterized for phase composition using X-ray diffractrometry (XRD) and Fourier transform infrared spectroscopy (FT-IR). © 2010 Elsevier Ltd. All rights reserved

Rapid synthesis and characterization of silicon substituted nano hydroxyapatite using microwave irradiation

Nano sized hydroxyapatites with silicon substitution of three different silicon concentrations were successfully prepared first time by a rapid microwave assisted synthesis method, with a time saving and energy efficient technique. The effects of the Si substitution on crystallite size, particle size and morphology of the powders were investigated. The crystalline phase, microstructure, chemical composition, and morphology and particle size of hydroxyapatite and silicon substituted hydroxyapatites were characterized by X-ray diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and Dynamic Light Scattering. The crystallite size and particle size decreases with increase in silicon content and particle morphology spheroidal for pure hydroxyapatite changes to elongated ellipsoidal crystals while silicon substitution increases. Fourier Transform Infrared Spectroscopy analysis reveals, the silicon incorporation to hydroxyapatite lattice occurs via substitution of silicate groups for phosphate groups. Substitution of phosphate group by silicate in the apatite structure results in a small increase in the lattice parameters in both a-axis and c-axis of the unit cell