Halloysite, Al2Si2O5·2H2O, is a naturally occurring two-layered alluminosilicate, chemically similarto kaolin, which has a predominantly high-aspect-ratio hollow tubular structure in thesubmicrometer range and an internal diameter in the nanometer range. The size of halloysitenanotubes (HNTs), generally varies from 50 to 70 nm in external diameter, ca. 15 nm diameterlumen, and 0.5 to 1 μm in length. Halloysite tubes have aluminol (Al-OH) groups on the internalsurface and siloxan groups (Si-O-Si) on the external surface.The very large diameter of the halloysite lumen makes it potentially suitable for the accommodationof a range of guests. In recent reports, for example, the mesoporous lumen of HNTs was used as ananoreactor to host reactants for nanosynthesis and biomimetic synthesis. Application of halloysite is severely limited by its hydrophilic internal and external surfaces.In order to improve the dispersion of HNTs in polymer matrix and synthesize great promise organiccomposites, a surface modification of halloysite is required. In this work we have developed a newsynthetic method, that consists in the grafting of organosilanes on the external surface bymicrowave irradiation. The f-HNTs can be employed as polymer filler and they can be subjected tofurther chemical modification by organic molecules such as ionic liquids.
MICROWAVE-ASSISTED FUNCTIONALIZATION OF HALLOYSITE NANOTUBE SURFACE
RIELA, Serena;
2014-01-01
Abstract
Halloysite, Al2Si2O5·2H2O, is a naturally occurring two-layered alluminosilicate, chemically similarto kaolin, which has a predominantly high-aspect-ratio hollow tubular structure in thesubmicrometer range and an internal diameter in the nanometer range. The size of halloysitenanotubes (HNTs), generally varies from 50 to 70 nm in external diameter, ca. 15 nm diameterlumen, and 0.5 to 1 μm in length. Halloysite tubes have aluminol (Al-OH) groups on the internalsurface and siloxan groups (Si-O-Si) on the external surface.The very large diameter of the halloysite lumen makes it potentially suitable for the accommodationof a range of guests. In recent reports, for example, the mesoporous lumen of HNTs was used as ananoreactor to host reactants for nanosynthesis and biomimetic synthesis. Application of halloysite is severely limited by its hydrophilic internal and external surfaces.In order to improve the dispersion of HNTs in polymer matrix and synthesize great promise organiccomposites, a surface modification of halloysite is required. In this work we have developed a newsynthetic method, that consists in the grafting of organosilanes on the external surface bymicrowave irradiation. The f-HNTs can be employed as polymer filler and they can be subjected tofurther chemical modification by organic molecules such as ionic liquids.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
