Study On The Synthesis Of Alternating Hydrotalcite-Montmorillonite Layered Hybrid

Hydrotalcite and montmorillonite have two-dimensional layered structure, and they are obtained easily. Currently, their research and application have made good progress. Hydrotalcite and montmorillonite have similarities in structure, but the charge between the nanosheets are completely contrary. These features make the hydrotalcite and montmorillonite assembled into a composite materials become a reality.Here, we used suitable surfactants to modify hydrotalcite and montmorillonite respectivelu with an increase of the interlayer spacings,and explored the optimal reaction conditions for different surfactant-modified montmorillonite, it proved that the longer the chain length of the surfactant can increase the interlayer spacings biger. Delamination of the surfactant layered solids was effected by dispersing the solid in chloroform solvent,the observed Tyndall light scattering indicating the presence of the exfoliated inorganic nanosheets dispersed in the chloroform solvent.When dispersions of the two solids are mixed and the solvent allowed to evaporate a new solid is obtained in which the hydrotalcite and montmorillonite sheets alternate in a periodic fashion with a repeat length different from that of the starting surfactant intercalated hydrotalcite and montmorillonite. By XRD, IR absorption, scanning electron microscopy (SEM), high resolution transmission electron microscopy(HRTEM) analysis demonstrated the synthesis of this composites, the XRD analysis of composite materials formed by MMT-CTAB and LDHS-SDS, low angle diffraction peak appeared at 2.20°, corresponding the layer spacing of 4.01nm. The low angle diffraction peak of composite materials formed by MMT-1827 and LDHS-SDS appeared at 1.99°, corresponding the layer spacing of 4.43nm, the effect is much better than the previous method,it can maintain laminate structure after calcination at 400℃,it has a good catalytic effect in methylesterification of linseed oil. This method is general, and should, in principle, be applicable to other layered solids that have been intercalated with appropriate long chain surfactants, the new materials would have more excellent performance in different areas and have a broad application.