A kaolinite-organic intercalation compound containing methanol was proved to be a versatile host for further displacement reaction with alkylamines. Kaolinite-organic intercalation compounds with polar molecules, such as N-methylformamide (NMF) and formamide, were used as the starting materials. After stirring the kaolinite-NMF intercalation compound with methanol, the basal spacing increased to 1.11 nm. The 13C MAS NMR result of the product indicated that methanol was intercalated into kaolinite by partial displacement with NMF. By use of the methanol-treated kaolinite intercalation compound as the intermediate, alkylamines were intercalated into the interlayer space of kaolinite by displacing with methanol.
A kaolinite-poly(b-alanine) intercalation compound (kaolinite/poly(b-alanine)) was synthesized by in-situ polycondensation of preintercalated b-alanine, which is an initial step toward the extension of the variety of host materials for polymer-clay nanocomposites. b-Alanine was intercalated into kaolinite by a displacement method using kaolinite/ammonium acetate as the intermediate. Zwitterionic b-alanine was ordered in a monolayer arrangement between the layers, which was confirmed by powder XRD, IR and NMR. Although b-alanine was mostly polymerized by thermal treatment of kaolinite/b-alanine at 250 uC for 10 h under an N 2 atmosphere, a part of the guest species was decomposed. Kaolinite/poly(b-alanine) had a higher thermal stability than bulk poly(b-alanine), as evidenced by TG-DTA.
Magadiite, a layered sodium polysilicate, was organically modified by esterification of
interlayer silanol groups with various aliphatic alcohols. Methanol was directly reacted with
H-magadiite (acid-treated magadiite) by refluxing. The methanol-treated product showed
an increase in the basal spacing and the 13C NMR signals due to methyl groups. The 2H
NMR spectrum of CD3OD-treated H-magadiite showed Pake doublet patterns of quadrupole
coupling constants of 43 and 48 kHz and asymmetry factors of 0, indicating the fixation of
the C−O axis. When aliphatic alcohols with the carbon chain length longer than 4 were
used, an H-magadiite/N-methylformamide (NMF) intercalation compound was used as an
intermediate for esterification. The basal spacing of butanol-treated H-magadiite was 1.40
nm, the value of which was smaller than that of H-magadiite/NMF (1.63 nm) and larger
than that of H-magadiite (1.15 nm). 13C spin−lattice relaxation times (T
1) of butyl groups
showed a low mobility of the α carbon. Other alcohols (C
n
H2
n
+1OH (n = 2−16) and (CH3)3COH) were also reacted with the silanol groups. The differential thermal analysis (DTA)
curves of the products showed exothermic peaks. The alkyl chains are apparently lying
parallel to the inner surface because almost constant basal spacings were observed despite
the variation in the alkyl chain length. The butanol-treated H-magadiite was dispersed in
toluene and cast, resulting in the formation of a transparent nanocomposite film.
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