Organofilização E Silanização De Argila Bentonita

Abstract

One of the most usual applications is their incorporation into organic materials. Nonetheless, natural clays are hydrophobic being incompatible with organic medium. Clay organophilization can be reached by several methods such as by exchange of the interlayer sodium cations by organic cations, and by silanization of the clay layers. In this study the bentonite clay was organophilized by the addition of the methoxymethyltriphenylphosphonium chloride (CTFF). Further, the organoclay was silanized with (3-glycidyloxypropyl) trimethoxysilane (GPTMS). X-ray fluorescence results, infrared and XPS spectroscopy showed the presence of phosphorus in the organophilic clay. The interlayer space, obtained by X-ray diffraction, increased in 55% after the CTFF addition showing the cationic exchange in the clay lamellar region. After the silanization of the organoclay the interlayer space was slightly reduced from 1,78 nm to 1,72 nm, indicating that the silane molecules were preferential bound in the clay edges.Keywords: organoclay; bentonite; silane; quaternary phosponium salt. INTRODUÇÃOA argila é definida como um material terroso, de granulação fina, apresenta alta plasticidade em água 1-3 e é formada pelo empacotamento de lamelas cristalinas.1,3-5 A bentonita uma das argilas de maior interesse tecnológico, 3,6,7 apresenta em sua configuração cátions interlamelares, que podem ser trocados por cátions orgânicos ou inorgânicos quando presentes em solução aquosa, influenciando suas propriedades físico-químicas e alterando seu espaçamento basal, essa propriedade é chamada de capacidade de troca catiônica (CTC). [2][3][4]8,9 O termo bentonita é comumente usado para designar argilas constituídas principalmente por argilomineral ou argilominerais esmectíticos, sendo o argilomineral mais frequentemente encontrado a montmorilonita. Essa classe de argilas é constituída principalmente por silicatos de alumínio e magnésio do tipo 2:1, no qual uma folha octaédrica está entre duas folhas tetraédricas. Esse silicato possui deficiência de cargas positivas em sua estrutura cristalina, resultando em excesso de cargas negativas, que é contrabalanceado por cátions interlamelares alcalinos, Na+ ou K+. A montmorilonita é caracterizada pela sua capacidade de troca catiô-nica, que permite que os cátions inorgânicos sejam substituídos por cátions orgânicos, aumentando seu caráter apolar, e possibilitando sua incorporação em meios orgânicos.3 Após a troca catiônica as argilas são denominadas argilas organofílicas ou organofilizadas, e a partir dessas é possível se obter complexos argila-compostos orgânicos.2,10 As argilas organofilizadas são mais facilmente incorporadas em sistemas orgânicos, como em cosméticos, tintas à base de solventes orgânicos, polímeros apolares e lubrificantes. A substituição de cátions de sódio por cátions orgânicos, em geral, causa um aumento da distância basal da argila, o que pode ser observado pela técnica de difração de raios-X (XRD) e, usualmente, quanto maior a cadeia orgânica do sal maior será a distância interlamelar ...

High‐density polyethylene/attapulgite (ATP) nanocomposites: Effect of the organophilization of ATP on the structural, mechanical, and thermal properties

“…With organophilization, the content of carbon decreased and the content of nitrogen and hydrogen increased when compared to ATPr. The variation in carbon content determined by CNH confirms the replacement of inorganic cations with organic cations 23,29 …”

“…The variation in carbon content determined by CNH confirms the replacement of inorganic cations with organic cations. 23,29 ATP is a 2:1 phyllosilicate that has continuous octahedral sheets in only one dimension and tetrahedral sheets also divided into a ribbon by inversion, with the apical oxygens pointing alternately up and down in adjacent strips, but still connected, resulting in a porous structure whose channels contain exchangeable cations. The polymer can permeate or penetrate between ATP clusters, distributing or individualizing these clusters, modifying the hydrophilic surface properties.…”

“…22 The salts used in the modification have one or two long-chain hydrocarbon groups directly linked to a nitrogen atom where the cationic part of the molecule is located. 23 These modifiers make it possible to decrease the surface energy of the nanoclay and can improve the wettability of the polymer matrix. This mechanism contributes to the penetration of polymer chains between the clay agglomerates, enabling distribution and dispersion in the polymer matrix and an increase in the adhesion between the polymer and the nanoclay.…”

“…These cations are easily exchangeable because they are monovalent and divalent that facilitate the exchange by organic cations of quaternary ammonium salts (cationic surfactants) or even other types of salts, in an aqueous solution 22 . The salts used in the modification have one or two long‐chain hydrocarbon groups directly linked to a nitrogen atom where the cationic part of the molecule is located 23 …”

Caracterização de filmes de polietileno de baixa densidade incorporados com diferentes concentrações de montmorilonita

“…However, studies reveal that this incorporation usually presents a weak interaction between the interfaces of the component (Luduena et al, 2007). These interactions can be achieved by the organofilization of the compounds in order to ensure better compatibility between the polymeric matrix and clays (Baruel et al, 2018;Paiva et al, 2008). Development, v. 9, n. 9, e696997914, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i9.7914 with the formula Mx(Al4-xMgx)Si8O20(OH)4 (Paiva et al, 2008).It exchanges inorganic cation for ammonium ions to improve its compatibility with polymers (Dutta & Singh, 2015;Paul et al, 2003).…”