Montmorillonite modified with ammonium

A phase-transfer catalyst such as tetra-n-butyl ammonium bromide has been used to chemoselectively epoxidize 1,4-units rather than 1,2-units in PBD [127] or HTPB [128] in a biphasic system. The degree of conversion accessible with peracids was up to 90% before the epoxidation of 1,2-vinyl groups was possible. Side reactions such as epoxide opening or oxidatimi of terminal hydroxyl groups have not been observed [128]. Modified clays (e.g., Closite 30B, a montmorillonite modified with ammonium salts) were also found to be favorable for epoxidation of cis-l,4-PBD because no phase-transfer agents need to be separated and phase transfer was not the rate-determining step [129,130]. 

Torok, B., Szollosi, G., Rozsa-Tarjani, M., Bartok, M. (1998) Preparation, Characterization and Application of K-10 Montmorillonite Modified with Chiral Ammonium Halides, Mo/. Cryst. Liq. Cryst., 311,289-294. 

Ray et al. [24] treated Cloisite 20A (montmorillonite modified with dimethyl-ditallow-containing approximately 65% Cig, 30% Cis, and 5% Ci4-ammonium cation chains) with a MAO solution, after vacuo-drying at 100 °C. The resulting MAO-treated clay was subsequently used for ethylene polymerizahon in the presence of a late transition metal catalyst (2,6-bis[l-(2,6-diisopropylphenylimino)ethyl] pyridine iron(ll) dichloride) and additional MAO in a glass reactor. They compared the result with homogeneous polymerization with the same catalyst in the presence of Cloisite 20A and observed that the supported catalyst was more efficiently exfoliated than when only a mixture of catalyst and clay was used. This comparison led them to conclude that at least some of the active centers resided within the clay galleries. Inductively coupled plasma (ICP) measurements showed that all MAO and catalyst remained in the solid catalyst after drying. 

TEM photomicrograph of a PMMA nanocomposite containing 5 wt% of size-fractionated bentonite clay (montmorillonite) modified with cetyl trimethyl ammonium bromide (at 1.9 cation exchange capacity [CEC]). (From K. R. Ratinac, R. G. Gilbert, L. Ye, A. S. Jones, and S. R Ringer, Polymer 47, 6337-6361, 2006. With permission.)... 

Montmorillonite modified with octadecyl ammonium cation. 

FIGURE 17.3 Dependence of cell size and cell density of PLA (NatureWorks 3000D, Cargill Dow) and PLA nanocomposites on the concentration of organically modified layered silicates (organoclay Cloisites 30B, Southern Clay Products, Inc., Texas) [42]. Cloisite 30B is the montmorillonite modified with methyl, tallow (-65% C18, -30% C16, -5% C14), and bis-2-hydroxy ethyl quaternary ammonium salt. 

C. B. Hedley, G. Yuan, and B. K. G. Theng, Thermal analysis of montmorillonites modified with quaternary phosphonium and ammonium surfactants. Applied Clay Science, 35 (2007), 180-88. 

Montmorillonite is usually modified with ammonium salts, in our study the selected ionic liquids were applied as modifying agents for the intercalation of montmorillonite. Surface properties of modified fillers, the zeta potential of suspended solids in the water, the oil absorption number, the impact of modifications on the tendency to agglomerate in the non-polar and polar medium were studied. 

TCN - montmorillonite modified with 25-30 wt% dimethyl, dihydrogenatedtallow, quaternary ammonium salt 2M2HT where HT is hydrogenated tallow ( 65% CIS, 30% C16, 5%C14) (Nanoclay, USA),... 

Fig. 3 SEM picture of montmorillonite modified with A) didecyldimethyl ammonium saccharinate...

As it was in case of HNBR vulcanisates the commercially modified MMT had negative effect on the ageing of the samples. The resistant against LTV radiation and atmospheric ageing of the vulcanisates containing montmorillonite modified with ionic liquids was higher in comparision to vulcanisate filled with ammonium salts modified MMT. 

Montmorillonite modified with a quaternary ammonium salt (Cloisite SOB) was purchased from Southern Clay Products Inc. Texas, USA. Cloisite 30A was dried for 6 h at 90°C in a thermal vacuum chamber. Poly(ethylene oxide) Mw 3000 g/mol, was dried in a vacuum oven (under lower pressure) at 90 C for 30 min before use. 4,4 -Methylenebis(cyclohexyl isocyanate) (HMDI), 1,4-butanediol (B), 1,2,3-propanetriol (G), triethanolamine (T), acetone were used without purification. All these materials were purchased from Sigma-Aldrich Co. 

Contrary to what many people think, PLSNs are not a recent discovery. One of the earliest systematic studies of the interaction between a clay mineral and a macromolecule dates backs to 1949, when Bower described the absorption of DNA by montmorillonite. Even in the absence of X-ray diffraction (XRD) evidence, this finding implied insertion of the macromolecule in the lamellar structure of the silicate. In the case of synthetic polymers, Uskov found in 1960 that the softening point of polymethylmethacrylate derived by polymerisation of methylmethacrylate was raised by montmorillonite modified with octadecyl-ammonium, while in the following year Blumstein obtained a polymer inserted in the structure of a montmorillonite by polymerising a previously inserted vinyl monomer. In 1965 Blumstein first reported the improved thermal stability of a PMMA/clay nanocomposite. He showed that PMMA inserted between the lamellae of montmorillonite clay resisted thermal degradation under conditions that would otherwise completely degrade pure PMMA." ... 

The presence of an organophilic clay increases the catalyst activity (10). Suitable clays include montmorillonite, hectorite, mica, etc. For example, Lucentite is a trioctylmonomethylammonium salt-treated synthetic hectorite. The clays are modified with quaternary ammonium compounds. The clays are heat treated prior to their use in the polymerization process. Further, the incorporated clay can improve the performance of the UHMWPE or function as filler. 

Montmorillonite clay modified with a quaternary ammonium salt... 

Sodium montmorillonite/PVK composites have been prepared by free radical polymerization using cerium ammonium nitrate [223]. Sodium montmo-rillonite was used in the form of nanolayers both of hydrophilic and organophilic types, modified with octadecylamine and trimethyl stearyl ammonium. 

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