Effect Of Sodium Dodecyl Benzene Sulfonate On Morphology And Structure Of Calcium Silicate Hydrate

Calcium silicate?CaSiO₃?materials have been widely used in traditional industry because of their unique physical and chemical properties and mineralogical characteristics.At the same time as calcium silicates have potential applications in biomedical fields such as bone tissue engineering and drug delivery owing to their comparatively good bioactivity,biocompatibilityandbiodegradability,andthus have recently drawn an increasing attention.Hollow micro-or nano-spheres have gained much attention as drug delivery materials owing to their low density,large surface area and surface permeability.However,the synthesis of calcium silicate based microspheres has not been well investigated,the soft-template method is a common method for the preparation of spherical shell materials,in which the micelle is a more commonly used kind of soft-templates.Based on the presence of Sodium Dodecyl Benzene Sulfonate?SDBS?,the synthesis,composition,structure and morphology of calcium silicate hydrate?CSH?with specific morphology were systematically studied.The main work and important achievements are as follows:CSH samples were prepared by chemical precipitation of calcium nitrate and sodium silicate.The effect of the concentration of SDBS and the drop adding sequence of reaction solution on the structure and morphology of calcium silicate hydrate were investigated by modern techniques such as X-ray diffraction?XRD?,Fourier transform infrared spectroscopy?FT-IR?and scanning electron microscope?SEM?.The order degree of CSH was studied by XRD technology.It was found that the concentration of SDBS and the drop adding sequence of reaction solution have effects on the structure and morphology of calcium silicate.When SDBS was added first,and then CSH was formed,when the concentration of SDBS was greater than that of the critical micelle concentration?CMC?,the order degree of CSH decreased;the order degree increased when it was less than CMC.When CSH was first formed and then SDBS was added,the order of CSH increased.The polymerization degree of Si-O of[Si O₄]^4-tetrahedron in CSH was qualitatively and quantitatively studied by FT-IR technology.It was found that the[Si O₄]^4-tetrahedron structure of CSH exists in the form of Q².When SDBS was added first,and then CSH was formed,when the concentration of SDBS was greater than that of the critical micelle concentration?CMC?,the polymerization degree of Si-O of[SiO₄]^4-tetrahedron increased and reduced when it was less than CMC.When CSH was first formed and then SDBS was added,the polymerization degree of Si-O of[SiO₄]^4-tetrahedron decreased.The microstructure of CSH has been studied by SEM.It was found that the morphology of CSH is closely related to the concentration of SDBS and the drop adding sequence of reaction solution.The main morphologies of calcium silicate hydrate are spherical shell and layered.According to the results of the characterization and the experience of the predecessors,the formation mechanism of spherical shell of calcium silicate hydrate was analyzed and summarized.