Ammonium cations intercalation

Fig. 9.1 Molecular dimensions of intercalants (A) octadecy-lammonium (C18H3N+), (B) octadecyltrimethylammonium (C18(CH3)3N+), (C) dioctadecyldimethylammonium (2C18(CH3)2N+), and (D) N-(cocoalkyl)-N,N-[bis(2-hydro-xyethyl)]-N-methyl ammonium cations (qC14(OH)). Reprinted from [18], 2006, Wiley-VCH.

Fig. 9.3 Illustration of a model of interlayer structure of intercalant N-(cocoalkyl)-N,N-[bis (2-hydroxyethyl)]-N-methyl ammonium cation (qCi4(OH)) in the gallery space of layered titanate (HTO). The average distance between exchange sites is 0.888 nm, calculated from the surface charge density of 1.26e /nm2. For qCi4(OH), the obtained molecular length,...

Fig. 2. Diagram showing the intercalation of compact quaternary ammonium cations, such as trimethylphenylammonium (TMPA) into different smectites, giving rise to type I organoclays with a basal spacing of about 1.5 nm. SWa is a high-charge nontronite (iron-rich smectite) and SAz is a high-charge montmorillonite, while SAC is a low-charge montmorillonite. After Jaynes and Boyd (1991b).

Layers of silicate-bearing hectorites were expanded by the intercalation of the lengthwise alkyl quaternary ammonium cation and simultaneously the interlayer anisotropic silicates stood normally to the layer. 

PCH materials offer new opportunities for the rational design of heterogeneous catalyst systems, because the pore size distributions are in the supermicropore to small mesopore range (14-25A) and chemical functionality (e.g., acidity) can be introduced by adjusting the composition of the layered silicate host. The approach to designing PCH materials is based on the use of intercalated quaternary ammonium cations and neutral amines as co-surfactants to direct the interlamellar hydrolysis and condensation polymerization of neutral inorganic precursor (for example, tetraethylorthosilicate, TEOS) within the galleries of an ionic lamellar solid. 

Stable colloids of nanometer-sized lamellar manganese oxides have been prepared by intercalation and self-assembly direct reduction methods. The structures, particle sizes, and optical properties of the materials have been described. Organic amine/ammonium species (TAA and DA) were used to intercalate birnessite H-OL-1 to prepare TAA-OL-1. Many kinds of structures and their formation processes were also described. The effects of organic ammonium cations and organic amines on the preparation of the manganese oxides were studied systematically. 

MPSj spontaneously reacts at room temperature with aqueous solutions of a wide variety of salts such as KCl, Co(C5Hj)2Cl or various ammonium chlorides. Intercalates Mn,i j,PS3(G)2,j(H20)y are formed, where the positive charge of the guest cations G is counterbalanced by the removal of an equivalent amount of intralamellar Mn ... 

Natural montroriUonite and organically modified MMT with methyl tallow bis-2-hydroxyethyl ammonium cations located in the silicate gallery (Cloisite 30B) were evaluted in starch-based nanocomposite [232]. It was observed that the TPS/ Cloisite Na-t nanocomposites showed higher tensile strength and thermal stability, better barrier properties to water vapor than the TPS/Cloisite 30B nanocomposites, as well as the pristine TPS, due to the formation of the intercalated nanostructure. Perez et al. [233] compared three different clays (Cloisite Na+, Cloisite 30B and Cloisite 10A) and found the best properties were achieved with Cloisite lOA due to their greatest compatibility with the matrix. 

Kurokawa et al. [258-260] developed a novel but somewhat complex procedure for the preparation of PP/clay nanocomposites and studied some factors controlling mechanical properties of PP/clay mineral nanocomposites. This method consisted of the following three steps (1) a small amount of polymerizing polar monomer, diacetone acrylamide, was intercalated between clay mineral [hydrophobic hectorite (HC) and hydrophobic MMT clay] layers, surface of which was ion exchanged with quaternary ammonium cations, and then polymerized to expand the interlayer distance (2) polar maleic acid-grafted PP (m-PP), in addition was intercalated into the interlayer space to make a composite (master batch, MB) (3) the prepared MB was finally mixed with a conventional PP by melt twin-screw extrusion at 180°C and at a mixing rate of 160 rpm to prepare nanocomposite. Authors observed that the properties of the nanocomposite strongly dependent on the stiffness of clay mineral layer. Similar improvement of mechanical properties of the PP/clay/m-PP nanocomposites was observed by other researchers [50,261]. 

Figure 7.7 XRD plots of organoclay (modified with octadecyl ammonium cation), epoxy/DDS/clay (intercalated) and epoxy/DETDA/clay (exfoliated) nanocomposites. Reprinted from D.Ratna, N.R. Manoj, R.K. Singh Raman, R. Varley and G.R Simon, Polymer International, 2003, 52, 9,1403 2003 John...

Intercalation of organic cations in smectites MontmoriUonite/aliphatic and aromatic ammonium cations Gieseking (11) and Hendricks (12)... 

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