Delicia Acosta

Preparation op metal borides in an aprotic system

Abstract A novel technique to prepare Nickel Borides using Diborane-THF complex generated “in-situ” as reducing agent, is presented. The Nickel Bondes series were prepared using two ways, the HETEROGENEOUS and HOMOGENEOUS route. Solid NiCls of different mesh size was added to the reducing complex to prepare nickel boride by HETEROGENEOUS route. While Ni(AcO) 2 ·4H 2 O dissolved in methanol was used to obtain nickel boride by the HOMOGENEOUS one. The advantage of this technique is that by using an aprotic medium, borides of metals which form stable oxoanions are obtained.

Effect of the Organoclay Preparation on the Extent of the Intercalation/Exfoliation and the Barrier Properties in Polyamide-6/Montmorillonite Nanocomposites

This paper shows the importance of the clay surface chemistry in the preparation of nanocomposite materials. An Argentinean montmorillonite was used for preparing two modified clays. The filosilicate was intercalated with a quaternary ammonium salt derived from ε- caprolactam to obtain an organofilic material. The other modification was introduced by mixing the clay with hexadecyl trimethyl ammonium chloride. Thus, the polyamide 6 ability in dispersing clays was applied to prepare composites with the intercalated clays. The polyamide 6/clay dry composites with 3 wt % of filler were prepared by melt processing in a mixer chamber. Composites of polyamide 6/organoclay were characterized by X-ray diffraction, transmission and scanning electron microscopy and thermogravimetry. The barrier properties were determined by cyclohexane pervaporation. The results show that the dispersion and degree of delamination depend on a proper chemical treatment and the clay content influences the polyamide 6 nanocomposites solvent pervaporation resistance.