Study on the Structure and Gelating Performance of Organically Modified Montmorillonite

摘要

Purified Na-montmorillonite samples were used as the starting materials to prepare organically modified montmorillonites (OM),and a series of OM samples were prepared by intercalation of alkyl quaternary ammoniums with different alkyl chain length.The interlayer spacing (d001) of the OM was determined by small angle X-ray diffraction and its gelating performance was characterized by measuring the viscosity of OM/dimethylbenzene mixture.The effects of alkyl chain length,dosage of alkyl ammonium,intercalation duration and layer charge of the starting material on the OM structure and gelating properties were investigated.According to the results,the adsorption quantity of the alkyl ammonium is dependent on the hydrocarbon chain length,the dosage of the alkyl ammonium and the retention time.The adsorption quantity of the alkyl ammonium increases with the chain length and the dosage,and extra adsorption more than the CEC of the montmorillonite sample was observed under the dosages of more than 1.3 CEC.The interlayer spacing (d001) of the OM shows a dynamic variation with the dosage and the retention time,and super interlayer spacings greater than the length of the alkyl ammonium were observed under larger dosages and shorter retention times.However,the gelating performance of OM does not follow the variations of the adsorption quantity of alkyl ammonium,an optimum viscosity value of OM/dimethylbenzene gel was observed with the moderate adsorption of the alkyl ammoniums.Furthermore,the layer charge plays an important role on the gelating performance of OM.The OM synthesized by the starting material with lower layer charge shows better gelating performance in the dimethylbenzene solution.