Keywords: calcium carbonate, nanoparticles, reverse microemulsion, co–surfactants, thermal properties, nanotechnology, thermal decomposition
Synthesis and modification of calcium carbonate nano–particles via reverse micro–emulsion method
Two reverse microemulsion system of surfactants (Span®80 and Tween®80)/Toluene/water was selected for synthesis of CaCO3 nano–particles. CaCO3 particles synthesised were surface modified by stearic acid. The effect of different concentrations of surfactants (span–80/tween–80) on the synthesis of nano–CaCO3 was investigated. The material was characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X–ray diffraction (XRD) and thermogravimetric analysis (TGA/DTA) techniques. XRD patterns confirmed spherical structure of nano–CaCO3 showing characteristic reflection of calcite phase. The size of the nano–particles was determined by TEM as well as XRD data for various concentrations of surfactants. The results showed that the size of the nano–particles was influenced by the concentration of the surfactants in the micro–emulsion system. TGA results demonstrated that decreasing the size of nano–particles resulted in the weight loss: these thermal decompositions may be attributed to calcite.