Clay nanoplate materials provide industries with special benefits due to their distinctive form and properties. Products containing clay nanoplate materials such as composite films and suspensions can be used for packages, seals, cosmetics, electronic devices and medicines. In order to support the transactions between manufacturers and users of clay nanoplate materials and their products, standardization for the materials/products was recently started by International Standardization Organization (ISO). Three standards have been developed or under development in ISO; two are for clay nanoplate materials and one is for polymeric composite films containing clay nanoplates. These standards require or recommend manufacturers of the materials/products to measure their characteristics and use the applicable measurement methods as well as to report the measurement results to the users of the materials/products. By using these standards, the buyers of materials/products can compare the characteristics of materials/products made by different manufacturers on the same basis and can ensure the quality of the materials/products transacted.

For the purpose of investigating the solid acidities of montmorillonite (MMT) for use as a catalyst, various MMT samples were obtained by purifying several bleaching earths from different localities. MMT has an interlamellar cation exchange capacity (CEC_i) originating in the isomorphous substitution in its layers, and MMT whose interlayer cations were exchanged with Al³⁺, Fe³⁺, Cr³⁺, Zn²⁺, NH₄⁺ and H⁺ showed solid acidity, while MMT whose interlayer cations were exchanged with Mg²⁺, Ca²⁺ and Na⁺ did not. Since the solid-state ³¹P NMR spectrum with magic angle spinning (MAS) of trimethylphosphine oxide (TMPO)-adsorbed H⁺-type MMT showed signals assignable to interlayer H⁺ at 58–54 ppm and signals assignable to H⁺ located in holes in the octahedral layers after migrating from the interlayer space at 69–64 ppm, the Brønsted acid site concentration in H⁺-type MMT was correlated with its corrected CEC_i, whose molar mass was corrected by the MMT content. The aspect ratios of dehydrated MMT particles were in the range from 1.7 to 11 and less than one-tenth compared with hydrated MMT, indicating that the effect of the edge surface area in H⁺-type MMT crystallite cannot be ignored. None of the Si–OH, Al–OH and Si–OH–Al groups present in the edge surface of H⁺-type MMT acted as solid acid sites. The Zn²⁺-type MMT possessed weak Lewis acid sites, and the bleaching earth possessed Lewis acid sites after calcining at above 600 K. After acid treatment, TMPO interacting with the bleaching earth surface showed a solid-state ³¹P MAS NMR signal at 67 ppm, which was identical to the signal position of TMPO interacting with H⁺-type MMT, and another at 71 ppm, which was similar to that of TMPO interacting with the silica–alumina catalysts. The Brønsted acid site concentration was larger than those of the silica–alumina catalysts.

The intercalation behavior of vanillin (VL), one of the most famous flavoring components having aldehyde structure, and its related compounds, m-anise aldehyde (MA) and 2-methoxyphenol (MP), into Mg–Al layered double hydroxide (LDH) has been examined by the calcination-rehydration (reconstruction) method using LDH oxide precursor at 25°C for 24 h. The molar ratio of the organic guest in aqueous solution to Al³⁺ ion in LDH oxide was set at 1.00 in all the experiments. The solid product was found to incorporate the guest depend on its structure together with hydroxide ion and to show the restorable LDH structure. The amounts of the organic guest intercalated (the guest/Al molar ratio of the solid product) were as follows: VL (0.81)>MP (0.41)>MA (0.18), and the effect of each substituent group of the guests was also discussed. In the case of vanillin isomers, the intercalated amounts were differently in the order; VL (0.81)>ortho-vanillin (0.58)>iso-vanillin (0.35), whereas the intercalated amounts of anise isomers were, on the whole, lower than VL isomers as MA (0.18)>ortho-anise (0.034)>para-anise (0.012). The XRD patterns of the solid products showed that VL was intercalated as a monovalent anion to make bilayer and to keep horizontal orientation for the LDH basal layer, and the others were intercalated to keep parallel orientation in the interlayer. Moreover, the results of the guest deintercalation (release) experiments from the solid products by ion exchange with chloride or carbonate ion revealed that the easier intercalated guest, the more difficult released one from the solid products.