Interlamellar amino functionalization of kaolinite

The interlamellar surface of kaolinite has been modified with molecules possessing amino functionalities. Either the dimethyl sulfoxide intercalate of kaolinite (Kao/DMSO) or the N-methylformamide intercalate of kaolinite (Kao/NMF) were used as starting materials. One of the products, an ethanolamine functionalized kaolinite (Kao-EOA) was resistant to thermal decomposition in both air and N 2 atmospheres up to temperatures greater than 150 °C. Based on results from thermal analysis, IR analysis, 13 CCP/MAS NMR spectroscopy, and elemental analysis, a structural model is proposed in which every third interlayer surface hydroxyl group on the aluminol (Al-OH) surface of kaolinite is either replaced with an interlayer Al-OCH 2 CH 2 NH 2 group or is strongly H-bonded to an aminoalcohol molecule. A mixture of both types of linkages could coexist. The amino groups that point away from this surface are each keyed into the -(SiO−) 6 macro-rings of the adjacent silicate surface, resulting in an amino-functionalized ordered two-dimensional organo-mineral assembly. Keywords: kaolinite, halloysite, organo-mineral nanocomposites, clay functionalization, supramolecular assemblies.