Distensibility of Bentonite Modified by Alkyl Quaternary Ammonium Salts

X-ray diffraction(XRD),fourier transform infrared spectrometer(FT-IR) and thermogravimetry(TG) analysis methods were applied to investigate the distensibility of bentonite modified by tetramethyl ammonium bromide(TMAB),tetraethyl ammonium bromide((Et)_4NB),dodecyl trimethyl ammonium bromide(DTAB) and hexadecyl trimethyl ammonium bromide(CTAB).The results show that different quaternary ammonium salts is adsorbed on the layer of bentonite,short chain quaternary ammonium salts exhibits excellent anti-swelling effect.The arrangement model of TMAB or(Et)_4NB is lateral-monolayer in the interlayer of bentonite,and the bentonite layer-spacing is decreased.Long chain quaternary ammonium salts make clay swelling,so it increases the layer-spacing of bentonite,the arrangement model of DTAB or CTAB is pseudo-trilayer and inclination etc in the interlayer of bentonite.Bentonite adsorption amount of(Et)_4NB or TMAB is less than that of DTAB or CTAB.