Single Kaolinite Nanometer Layers Prepared by an In Situ Polymerization–Exfoliation Process in the Presence of Ionic Liquids

Abstract

A simple chemical route for the exfoliation of kaolinite in the presence of polymerizable ionic liquids and the resulting obtainment of exfoliated nanocomposites is reported. The exfoliation was achieved using three different ionic liquids structurally bearing a vinyl group: 1-methyl-3-(4-vinylbenzyl)imidazolium chloride salt (IL_1), 1-methyl-1-(4-vinylbenzyl)pyrrolidinium chloride (IL_2), and 1-methyl-3-vinyl imidazolium iodide (IL_3) and a urea-kaolinite intercalate as precursor. The reaction was done in one step by an in situ polymerization-exfoliation process. (13)C CP/MAS NMR spectra confirmed the spontaneous polymerization of the ionic liquid during the exfoliation process to afford atactic polystyrene derivatives in the case of IL_1 and IL_2. The amount of organic material in the exfoliated nanocomposite was close to 30% as shown by thermal gravimetric analysis. This amount is small in comparison to the amount obtained when the exfoliation was done using sodium polyacrylate (Letaief and Detellier, Langmuir2009, 25, 10975). XRD as well as SEM analysis confirmed a total exfoliation of the kaolinite when the reaction was done using urea kaolinite, whereas a microcomposite, made predominantly of kaolinite platelet aggregates dispersed in the polymeric matrix, was formed when dimethylsulfoxide kaolinite was used as the precursor.

Evaluation of some intercalation methods of dimethylsulphoxide onto HCl-treated and untreated Egyptian kaolinite

“…No change in position was observed in the DMSO-kaolinite samples which indicate that the layers remained unaffected which was similarly observed elsewhere (Letaief et al, 2011). However, a broadening was observed that may be attributed to a perturbation of the crystal structure.…”

Kaolinite Clay Mineral Reactivity Improvement through Ionic Liquid Functionalization

“…These polymerizable ILs (1‐methyl‐3‐(4‐vinylbenzyl) imidazolium chloride salt (IL‐1), 1‐methyl‐1‐(4‐vinylbenzyl) pyrrolidinium chloride (IL‐2), and 1‐methyl‐3‐vinylimidazolium iodide (IL‐3)) were characterized by the presence in their structure of a vinyl group for the polymerization reactions under controlled experimental conditions. In this case, in order to avoid fast and uncontrolled polymerization of the monomers, the intercalation followed by polymerization was performed in one step in isopropanol at 90 °C . The obtained nanocomposite showed complete exfoliation when the urea pre‐intercalate was used for the synthesis.…”

The performance of chemically and physically modified local kaolinite in methanol dehydration to dimethyl ether

“…The second step in weight loss ranged from 5.5% to 3.5% with the same abovementioned order. In this step, water is lost due to the thermal dehydroxylation process [21,26,41] or conversion of hydroxide compounds to oxide sample by desorption of water. The weight loss of KB is more than KB-Ca, which indicated grafting of the sulfate group on end capped and surface hydroxyl groups.…”