Intercalating Cationic Surfactants in Koppies Bentonite

Abstract

Single and double chain cationic surfactants were intercalated into Koppies bentonite. The state of the chains in the interlayers was probed using XRD, FTIR spectroscopy and thermogravimetric analysis (TG). The degree of intercalation was determined by TG and exceeded the CEC equivalent value by 30-40 %. The degradation onset temperature of about 200 ºC was independent of the number and length of alkyl chain substituents. The XRD d-spacing was consistent with monolayer interdigitated surfactant intercalation for the C12 and C14 single chain surfactants and with bilayer intercalation of the double chain surfactants. FTIR analysis revealed disordered alkyl chain conformations.

EVA nanocomposites based on South African Koppies clay

“…The observed XRD d ‐spacing for the single‐tail surfactant organoclay sample was 1.92 nm. As previously reported , this value is consistent with interdigitated monolayer surfactant intercalation of the SC12. As mentioned before, samples prepared in the presence of excess of C12 surfactant featured a nearly identical XRD diffractogram and surfactant content.…”

“…Massinga et al and Massinga and Focke provide more detailed information on the characterization for the present, as well as some other organoclays. Fourier‐transform infrared (FTIR) data can establish whether the surfactants indeed intercalated and allow one to probe the state of the chains in the clay galleries.…”

“…We pose the following tentative rationalization for the results presented in this work. XRD results indicated interdigitated monolayer intercalation of the single‐tail surfactant in the clay, whereas the double‐tail surfactant intercalated in a double‐layer fashion . Basal spacing values of the neat organoclays were readily determined as the XRD diffractograms showed clear basal reflections.…”

“…The supplier stated a clay CEC of 85 meq/100 g dry clay according to the methylene blue method . The clay was organomodified by intercalation with cationic surfactants (Quats) by using the procedures previously reported . A Quat with a single long‐tail plus one polar hydroxyethyl group as well as one with two long alkyl chains were utilized.…”