Sarkar, Madhuchhanda and Dana, Kausik (2022) Intercalation of montmorillonite with dialkylammonium cationic surfactants. Journal of Molecular Structure, 1256. Art No-132468. ISSN 0022-2860

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Abstract

Three montmorillonite (Mt) clays with different cation exchange capacity (CEC) were intercalated by a series of dialkyl ammonium cations with carbon numbers (Nc= ) 8, 10, 12 and 18 in each alkyl chain. The intercalated clays were characterized by X-ray Diffraction, Thermogravimetric Analysis, Fourier Transform Infrared Spectroscopy and Transmission Electron Microscopy. The basal spacing of intercalated Mts in-creased gradually with increasing chain length. Interlayer arrangement of dialkyl surfactant cations in the intercalated clay gallery changed from flat bilayer to paraffinic and reached as high as 3.57 nm for the highest CEC clay intercalated with cations having Nc= 18 in each alkyl chain. For dialkylammonium inter-calants, the increase in basal spacing was predominantly guided by the intercalant's structure and organic loading values lacked such direct correlation. Mt with low CEC showed large expansion in the clay inter-layer with increasing alkyl chain length even with marginal increment in the organic loading. The highest basal spacing was observed always with the highest CEC clay for every intercalant irrespective of alkyl chain length. The wide expansion of clay gallery for the longest dialkyl intercalant in this series for all clays might be attributed to presence of intercalated surfactant molecules along with physically adsorbed surfactant cations in the clay interlayer. The change in conformations of intercalated dialkyl ammonium intercalants with increasing alkyl chain length was analyzed from FTIR study. With increasing alkyl chain length, methylene symmetric and asymmetric stretching frequency shifted to lower wavenumber for all Mt clays-which indicated greater ordered conformations obtained with increasing alkyl chain length.(C) 2022 Elsevier B.V. All rights reserved.

Item Type:	Article
Subjects:	Refractories
Divisions:	Refractory
Depositing User:	Bidhan Chaudhuri
Date Deposited:	20 Sep 2023 11:23
Last Modified:	20 Sep 2023 11:23
URI:	http://cgcri.csircentral.net/id/eprint/5518

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