title: [Synthesis of nanometer hydroxyapatite by sol-gel method].
abstract: OBJECTIVE
  To synthesize nanometer hydroxyapatite (HAP) by sol-gel method from Ca (NO3)2.4H2O and PO (CH3O)3 with water and ethanol as solvents and to study the factors that can affect the formation of sol-gel, including the type of solvents, amount of solvents, pH value, as well as properties under the condition of low temperature combustion of dried gel.
  
  
  METHODS
  The viscosities of sol were determined on WU viscosimeter. TG-DTA was used to analyze the thermal procedure of dried gel by increasing temperature. Characterization of the dried gel and powder after combustion were evaluated by X-ray diffraction and infrared spectrum. The morphology of the powder was observed by transmission electron microscopy.
  
  
  RESULTS
  Stable and homogeneous gel could be obtained at appropriate pH value when ethylene glycol was added into solvent. The dried gel had the feature of low temperature combustion. HAP powder with particle size of 50 nm was directly prepared.
  
  
  CONCLUSIONS
  Nanometer HAP powder with uniform particle size can be synthesized by sol-gel method.
authors.affiliation: Institute of Biomaterials, East China University of Science and Technology, Shanghai 200237, China. wpfyy@263.net
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yuan
authors.forename: Chang-sheng
authors.initials: CS
authors.lastname: Liu
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis; D017886:Durapatite; D005782:Gels; D036103:Nanotechnology; D010316:Particle Size; D012997:Solvents
chemical_list: D001672:Biocompatible Materials; D005782:Gels; D012997:Solvents; D017886:Durapatite