原位沉析法制备碳酸钙/壳聚糖三维复合材料的研究

将含有Ca²⁺的壳聚糖溶液与含有CO^2-₃的碱溶液用离子可渗透膜隔离,根据膜渗透原理,使膜内壳聚糖与碱液原位沉析,生成碳酸钙,得到具有高强度的碳酸钙(CaCO₃)/壳聚糖(CS) 三维复合材料. XRD测试结果表明,生成的碳酸钙以方解石晶型存在. 从SEM可以观察到碳酸钙颗粒尺寸约为5～10 μm,并且颗粒呈有序分布,它们以棒材的纵轴为中心,围绕中心呈环状分布. 对不同碳酸钙含量的复合棒材进行了弯曲性能测试,其弯曲强度随碳酸钙含量的增大先上升后下降. 在碳酸钙质量分数为10％时,弯曲强度达到最大值(约为113 MPa),弯曲模量为2.6 GPa.

Preparation of CaCO 3/Chitosan Three-dimentinal Composite Material via in-situ Precipitation

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.