Properties of polyethylcyanoacrylate/modified Mt composites with highly exfoliated montmorillonite
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Properties of polyethylcyanoacrylate/modified Mt composites with highly exfoliated montmorillonite Mohamed Fekry1 · Azza M. Mazrouaa1 · Manal G. Mohamed1 · Dalia E. Abulyazied1,2 Received: 3 August 2020 / Revised: 17 September 2020 / Accepted: 2 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The surface mineral modification of montmorillonite (Mt) layers was carried out by removing some of the exchangeable cations and anions (salts) using dimethylformamide as a chelating agent. The rest unremoved exchangeable cations were balanced by the permanent negative charges in the Mt layers. The modified Mt layers were characterized by X-ray fluorescence, high-resolution scanning electron microscopy (HR-SEM), dynamic light scattering (DLS), and high-resolution transmission electron microscopy. The completely exfoliated modified Mt layers were composed of polyethylcyanoacrylate (PECA) at different ratios 1, 3, 5, 7, 10, and 15% (wt/wt). The obtained composites were investigated by molar mass, FTIR, small-angle X-ray diffraction, wide-angle X-ray diffraction, HR-SEM, DLS, and TGA. The results showed that the exchangeable cations and anions (salts) were removed from the surfaces of Mt layers, and all the percentages of loaded Mt layers were completely exfoliated in the bulk of PECA. TEM morphology exhibited clearly separated modified Mt layers due to removing the salts. SEM morphology showed highly exfoliated modified Mt layers in PECA bulk. TGA and nanoindentation data were showed increases in both thermal stability and mechanical properties of prepared composites by increasing the ratios of modified Mt layers in the bulk of PECA. Keywords Montmorillonite minerals · Chelation · Clay exfoliation · Surface area · X-ray diffraction
* Mohamed Fekry [email protected] 1
Polymer Lab, Department of Petrochemical, Egyptian Petroleum Research Institute, Nasr City, Cairo, Egypt
2
Department of Physics, Faculty of Science, University of Tabuk, Tabuk, Saudi Arabia
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Vol.:(0123456789)
Polymer Bulletin
Introduction The silicate layers in montmorillonite clay have slight negative charges, and they were balanced by exchangeable cations like (K+, Na+, Ca2+, Mg2+ ions). The clay minerals were classified into two categories according to the percentage of cations in the silicate layers. The first one is the cation-poor, it has low cation–exchange capacities, they do not have a large number of ionic interactions to hold the clay layers together, so the clay layers were easily separated from each other. In contrast, the second one is cation-rich [1, 2]. There are different ways to improve the exfoliation of clay layers tactoids into separated layers. Among these methods was the solvent-exchange method; it was performed by dispersing the clay layers into deionized water and dissolving the polymer in dimethylacetamide; then, two solutions were mixed to produce full miscible liquid, after that the deionized water was removed by heating [3]. In the chelation method, it was taken place by
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