Aluminosilicate Nanocomposite Materials. Poly(ethylene glycol)−Kaolinite Intercalates

Abstract

This paper reports the first example of the direct intercalation of an organic polymer into the interlamellar spaces of kaolinite. Poly(ethylene glycols) (PEG 3400 and PEG 1000) were intercalated into kaolinite by displacing dimethyl sulfoxide (DMSO) from the DMSO−kaolinite intercalate (Kao−DMSO). This was done directly from the polymer melt at temperatures between 150 and 200 °C. XRD showed that the intercalated oxyethylene units were arranged in flattened monolayer arrangements, such that the interlayer expansion was 4.0 Å. Infrared analysis of Kao−PEG 3400 supported the assignment of a trans conformation to at least a portion of the (O−CH2CH2−O) groups of the PEG polymer while 13C CP and DD/MAS NMR indicated that the polymer was intercalated intact and was more constrained in the interlamellar spaces of kaolinite than it was in its bulk form. TGA/DSC analysis revealed that the complete decomposition of the organic component of the oxyethylene-based organokaolinites did not occur until greater than 1000 °C. The formulas were estimated to be Al2Si2O5(OH)4(−OCH2CH2−)0.77(DMSO)0.27 and Al2Si2O5(OH)4(−OCH2CH2−)0.99(DMSO)0.17, respectively for the cases of PEG 1000 and PEG 3400. The calculated formulas for both samples are consistent with one unit of oxyethylene or DMSO per Al2Si2O5(OH)4 unit. Given the known density of hydroxyl groups on the aluminol surface, a polymer conformation where ethyleneoxy groups repeat every 2.8 Å with the oxygens all facing toward the hydroxyl surface should be favored. It is suggested that the polymer adopts a conformation TG2T‘G2‘, in which the repeat unit per ethyleneoxy group is 2.94 Å, and all the oxygens are lined up on one side of the chain. The tension resulting from the imperfect fit could be relaxed by a certain degree of trans conformations.

Low frequency dielectric relaxation processes and ionic conductivity of montmorillonite clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone)−ethylene glycol blends

“…The XRD study of these materials confirmed that the intercalated oxyethylene units are arranged in flattened monolayer arrangements with 4 Å interlayer expansions [5]. It is supported by trans conformation to at least a portion of (O-CH 2 -CH 2 -O) groups of the PEG chain [48]. Furthermore, the main driving force for the intercalation reaction results from orientation of the polymer chains such that they form hydrogen bond with the hydroxylated aluminate surfaces of the clay.…”

“…The structural properties and dynamical behaviour of these phases governs the electrical conductivity of the organic-inorganic nanocomposite [45]. The PEO-clay and PEG-clay nanocomposites are extensively attempted to make potential electrolyte material for rechargeable batteries [8,9,[46][47][48][49][50][51][52]. Different spectroscopy investigation on poly(ethylene oxide) PEO-clay nanocomposites [46] confirmed that the intercalated PEO molecules between silicate galleries impede the polymer crystallization, which results in higher electrolyte conductivity compared to the system without clay.…”

“…For this the distances between oxygens in the polymer chain is roughly comparable to the distances between hydroxyl groups in clay sheets. For clay, interhydroxyl distance is ~2.8 Å, and the oxyethylene group repeat every 2.8 Å all facing towards the surface of clay would be particularly favourable [48]. In case of MMT clay colloidal suspension in PVP-EG blends, the intercalated EG structures can be assumed like the intercalated PEG and PEO structures, because the EG molecules have repeat units of PEG and PEO molecules.…”

Comportamento térmico da caulinita hidratada

“…A intercalação de algumas moléculas particulares somente é possível através do deslocamento de outras moléculas previamente intercaladas [10][11][12][13][14][15][16] . Recentemente, a intercalação de polímeros também foi reportada 12,[17][18][19][20] utilizando-se a metodologia de intercalação do precursor seguida de polimerização térmica 12,20 , intercalação do polímero fundido com caulinita previamente expandida 17,18 , ou deslocamento de moléculas de água previamente intercaladas 19,20 . Um dos derivados obtidos durante o processo de lavagem da caulinita previamente intercalada é a caulinita hidratada [21][22][23] .…”

Influence of Annealing Temperature on Electrical Properties of Unmodified Bentonite

“…According to these papers [4]- [6], the clay mineral includes two layers of silicon-oxygen tetrahedral, facing each other by their peaks, that on both sides covered by the layer of Aluminohydroxyl octahedral, which in general appears to be a three-layer packet (2: 1).…”