[Synthesis and characterization of CTMAB and PDMDAAC modified organobentonite]

The natural bentonite was purified and changed to sodium form by NaCl via exchange reaction. Their characteristics, such as swelling volume, swelling value, colloid valence, ethylene blue adsorbed and cation exchange capacity, were measured. The results indicate that the property of Na-bentonite is better than that of natural bentonite. Using cetyltrimethylammonium bromide (CTMAB) and homopolymer of dimethyldiallyammomium chloride (PDMDAAC) as organo-intercalating reagents, two organic modified bentonites were prepared and characterized by Fourier transform infrared (FTIR), X-ray powder diffraction (XRD) and BET surface area. The XRD results showed that the CTMAB-bentonite and PDMDAAC-bentonite had typical X-ray diffraction peaks, and the d001 values increased to 1.89 and 1.45 nm, respectively. Combined with the results of FTIR, the modified reagents had been intercalated to the layer of bentonite. The BET areas, pore volumes and average pore diameters of the two organo-bentonites were decreased as compared to that of Na-bentonite.