Synthesis of organoclays using non-ionic surfactants: Effect of time, temperature and concentration

The objective of the present research was to investigate the intercalation of three different polymer-based surfactants, namely polyethylene-glycol 1500 and 4000 (PEG 1500 and PEG 4000) and polyethylene-oxide (BRIJ 78), inside the interlayer of STx-1 montrnorillonite. The effect of three parameters, such as time (30, 60, 90 min), temperature (30 and 60 degrees C) and initial concentrations in solution (45, 90, and 180 mM) was studied. A full microstructural characterization of the synthesized organoclays by XRD, FT-IR, and TG-DTA was performed. The quantification of polymer intercalated was estimated by COD (Chemical Oxygen Demand) analysis of the residual amount in solution. The intercalation was successful, as showed by the basal expansions detected by XRD, and confirmed by FT-IR, showing the typical C-H-stretching bands in the spectra of the synthesized clays. TG-DTA was not a reliable technique for the quantification of polymer intercalated, while COD correctly quantified such amounts. The role of temperature and time appeared to be uninfluent for intercalating the polymer inside the interlayer of STx-1 montmorillonite, while the driving parameter ruling the amount of intercalated polymer was the initial concentration in solution. (C) 2009 Elsevier B.V. All rights reserved.