Impregnation Of Nanotubes Research Articles

Low-Dimensional Hollow Nanostructures: From Morphology Control to the Release of an Active Pharmaceutical Ingredient

The mechanism guiding the growth of hollow silica nanotubes or nanospheres was unveiled for the first time through in situ liquid-phase transmission electron microscopy, allowing visualization of the morphology of the hydrated species involved in the early stage of material formation. The combined action of a surfactant (F127) and a swelling agent (toluene) was essential for the development of targeted nanostructures, owing to the formation of surfactant-stabilized toluene droplets in the aqueous phase. The quantity of surfactant-stabilized toluene droplets was unambiguously pointed as the key parameter guiding the formation of either tubular or spherical nanostructures. Leveraging on the fundamental understanding of the parameters guiding the formation of hollow silica nanostructures, tubular and spherical carriers were prepared and exploited for the release of an active pharmaceutical ingredient (API). The impregnation of nanotubes and nanospheres with a poorly water-soluble API (curcumin) was investigated, leading to an optimal loading of 20 wt %. The accessibility of nanotubes and nanospheres showed to be highly beneficial to increase the release kinetics of the targeted API in simulated intestinal fluid, opening promising perspectives in the field. Release was more efficient than with other conventional mesoporous silica-based carriers.

Multiwalled carbon nanotubes impregnated rubber nanocomposites: thermal transport/decomposition and differential scanning calorimetric study

In order to analyze the effect of multiwalled carbon nanotubes on the thermal transport/stability characteristics of styrene butadiene rubber, five diverse loadings of multiwalled carbon nanotubes were impregnated in the rubber matrix using dispersion kneader and two roller mixing mill. Thermal conductivity and thermal impedance of the nanocomposite specimens were evaluated according to ASTM E1225-99 and D5470-03. It was observed that the thermal conductivity was reduced up to 79% while thermal impedance of the polymer nanocomposite was improved up to 390% at 523 K with 1 wt% impregnation of nanotubes into the base composite formulation. Thermal stability of the polymer nanocomposite was augmented up to 6%, with the utmost incorporation of the nanotubes. Glass transition and crystallization temperatures were diminished, while the onset and peak melting temperatures were increased with increasing filler to matrix ratio. The percent crystallinity of the nanocomposites has been augmented up to 5%, with 1 wt% incorporation of multiwalled carbon nanotubes into the host matrix. Scanning electron microscopy along with energy dispersive X-ray spectroscopy was used to examine the multiwalled carbon nanotubes dispersion in the rubber matrix, for surface analysis of the post-thermally tested composite specimens and for their compositional analysis.