室温下,在乙醇或乙醇-水混合体系中,利用氨基酸表面活性剂N-酰基十二烷基肌氨酸钠(Sar)调控合成碳酸钙,采用SEM,XRD和FTIR等技术表征了反应产物.在乙醇体系中,首先形成多面体形状的文石,然后逐渐转变为圆球状的无定形碳酸钙.在乙醇-水混合体系中,合成了花簇状多级结构碳酸钙晶体.增加N-酰基十二烷基肌氨酸钠的用量有助于形成球霰石结构,当n(Ca^2+):n(Sar)=1:1时,得到的花状碳酸钙为球霰石和方解石的混合物,当n(Ca^2+):n(Sar)=1:2时,得到纯净的球霰石,其形貌为大小较均一的单分散的球,直径约为7μm;另外,当n(Ca^2+):n(Sar)=1:1时,混合溶剂中水和乙醇的体积比由1.5:1依次增加为7:3和3:1时,碳酸钙晶体的形貌由花状逐渐向球形过渡,晶体中球霰石和方解石的含量也随之变化,其中,当水和醇的体积比为7:3时,产物主要为球霰石型晶体.
N-Lauroylsarcosine sodium(Sar-Na) was used to control calcium carbonate crystalization in ethanol or ethanol/water solution at ambient temperature. By means of SEM, XRD and IR, the morphology and structure of the samples were characterized. It is revealed that with increasing the reaction time, the morphology of the CaCO3 particles generally varies from aragonite polyhedron to amorphous calcium carbonate spheres in pure ethanol and in the ethanol/water solution, with increasing the amount of N-lauroylsarcosine sodium, the morphology of the CaCO3 particles varies from flower-like to spheres. Pure vaterite crystals with a spheres shape were obtained at n(Ca^2+) : n(Sar) = 1 : 2. At a fixed n(Ca^2+ ) : n(Sar) = 1 : 1, with increasing the volume fractions of distilled water, the morphology of the CaCO3 particles varies from flower-like to spheres.