Abstract:

A widely used inorganic compound in laboratory,CaCO₃/chitosan composite with high performed and potential applicable prospects,was prepared by the method of in-situ precipitation. In this method the calcium ions were added into the solution of chitosan firstly and were dispersed homogeneously to attain the uniform solution. Then the uniform solution as the CaCO₃/chitosan precursory solution was poured into a cylindrical glass mold,on the internal surface of which a chitosan membrane had been precipitated. Afterward the mold was soaked in the mixture of NaOH  and Na₂CO₃ aqueous solutions. Finally through the following proceedings,the three-dimensional composite in which the particles of calcium carbonate were dispersed was achieved in the experiment. XRD were carried out to determine the presence of the calcium carbonate. SEM was preformed to investigate the distributing regularity of calcium carbonate and the size of the calcium carbonate particle. It could be seen that the particles of orbicular were distributed orbicularly on the cross section and its size was about 5-10 μm. The mechanical properties of the composite were evaluated by three-point bending test. The bending strength enlarged firstly and then dropped with the increase of calcium carbonate′s mass fraction and the modulus decreased continuously.

Key words: Chitosan; Calcium carbonate; In-situ precipitation; Three-dimensional composite material