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Imogolite is one of the aluminosilicates with a chemical formula of Al 2 O 3 SiO 2 (H 2 O) n , consisting of hollow nanotubes with an external diameter of about 2.5 nm and a length from several hundred nanometers to a micrometer. Atomic force microscopic (AFM) observation revealed that the imogolite molecules form a fibrous network at pH=3.0. Since the outer surface of imogolite consists of the Al-OH group, a strong interaction can be expected between the Al-OH and the -PO(OH) 2 groups. Octadecylphosphonic acid (OPA) was chosen as a model amphiphilic molecule, and it chemisorbed onto the surface of imogolite. Surface coverage of imogolite with OPA was confirmed by infrared spectroscopy, thermogravimetric analysis, and adhesion force measurement by (AFM). The OPA-chemisorbed imogolite was dispersed in hexane whereas it forms precipitates in water. Since imogolite engages in a specific interaction with -PO(OH) 2 groups, it is expected that imogolite can be molecularly dispersed in -PO(OH) 2 group-modified poly(vinyl alcohol) (PVA). Temperature dependence of dynamic viscoelasticity exhibited a higher temperature shift of the α a -absorption of the matrix phosphorylated PVA for the (imogolite/phosphorylated PVA) hybrid compared with that for phosphorylated PVA. [ABSTRACT FROM AUTHOR]

Abstract: Novel polymer nanohybrid was prepared by free radical polymerization of methyl methacrylate in the presence of inorganic nanofiber ‘imogolite’ as reinforcing nanofiller. Imogolite is a hydrous aluminosilicate with a unique nanofiber structure. The surface of imogolite was modified with 2-acidphosphoxyethyl methacrylate, which has a polymerizable methacrylate group and a phosphoric acid moiety, before preparation of polymer hybrid. The polymer nanohybrid was prepared by free radical polymerization in the presence of surface modified imogolite. The mechanical properties of (PMMA/modified imogolite) hybrid with the modified imogolite were improved in comparison with those of PMMA and (PMMA/unmodified imogolite) blend. Furthermore, the hybrid film prepared from the surface modified imogolite kept the transparency similar to PMMA film. These results indicate the usefulness of the surface modification method with phosphoric acid groups and imogolite nanofibers as a reinforcing material. [Copyright &y& Elsevier]