Abstract: Polymer-ceramic nanocomposites with controlled dielectric properties are prepared using
poly(dimethylsiloxane) elastomer as base matrix and barium titanate as filler. Barium titanate
(BaTiO3) used in this study is prepared by solid state reaction at high temperature. The effect of
BaTiO3 nanoparticles on electrical and mechanical properties are extensively studied and found that
dielectric constant of nanocomposites increases significantly with the increase in BaTiO3
concentration where as volume resistivity decreases continuously. Different mechanical properties
are also studied for all the composites in order to find the effect of filler concentration. Morphology
of the prepared BaTiO3 was studied by field emission scanning electron microscope (FESEM).
Abstract: Flexible polyurethane (PU)–titania nanocomposites of different compositions are prepared by a meltmixing
technique. Two different sequences of mixing method are adapted to prepare two different sets of
composites. All these composites show composition-dependent dielectric properties, and composites with
tunable dielectric properties can be obtained through judicial adjustment of composition. The morphology
of these composites has been investigated by field emission scanning electron microscopy (FESEM), high
resolution transmission electron microscopy (HRTEM), and scanning probe microscopy (SPM). Dielectric
properties at low frequency regions are found to depend on morphology. These composites show
excellent piezoelectric behaviour, where the dielectric constant and conductivity of these flexible
composites change appreciably with changes in applied stress. The dielectric breakdown strength of these
composite is also measured. To understand the thermal stability of these composites, thermogravimetric
analysis has been applied and it was found that a composite containing 12.49 vol% titania shows higher
thermal stability, beyond which, stability decreases due to the photocatalytic effect of titania.
Abstract: Polymer–ceramic composites were prepared using poly(dimethylsiloxane) as base matrix and normal as well as heattreated
titania as fillers. Dielectric and mechanical properties of the composites were measured and found that dielectric constant of
the composites was increased dramatically with the addition of filler, whereas resistivity was decreased. Hardness and modulus were
found to increase but tensile strength, % elongation at break, and tear strength were decreased with the filler loading. Neat titania
contains some moisture (physisorbed and chemisorbed) as revealed from thermogravimetric analysis. Both electrical and mechanical
properties of the composites were affected by filler heat treatment. Further, untreated titania contains Ti3þ and Ti4þ, which on heat
treatment, increases the concentration of Ti4þ, as a result electrical properties were affected. Filler dispersion in the composites was
studied by field emission scanning electron microscopy and high resolution transmission electron microscopy.
Abstract: In this study, mesoporous silica encapsulated with magnetic MnFe2O4 nanoparticles is synthesized by
a solvothermal method. The synthetic route is feasible and widely applicable. The obtained products
have been characterized by an X-ray powder diffraction (XRD) pattern, field emission scanning
electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution TEM
(HRTEM) and nitrogen adsorption–desorption isotherm measurements. The synthesized magnetic
mesoporous MnFe2O4 nanoparticles are monodispersed with a mean diameter of 200 nm, and have
an obvious mesoporous silica shell of B20 nm. The surface area of magnetic mesoporous MnFe2O4
nanocomposites is 423 m2 g1. The nanoparticles are superparamagnetic in nature at room
temperature and can be separated by an external magnetic field. This magnetic mesoporous material
is used as a catalyst for the degradation of methyl orange dye. The merits of the effect under different
conditions like pH, temperature, light and sonolysis have been evaluated by investigating the
degradation of azo dye. The mesoporous MnFe2O4 nanocomposites have effective adsorption of dyes
inside the porous network followed by degradation with the central magnetite core and regeneration
of the catalyst with the help of a simple magnet for successive uses.
Abstract: Corrosion resistance behavior of sol–gelderived
organic–inorganic nanotitania–silica composite
coatings was studied. Hybrid sol was prepared from
Ti-isopropoxide and N-phenyl-3-aminopropyl triethoxy
silane. The structure, morphology, and properties
of the coating were characterized by Fourier transform
infrared spectroscopy (FTIR), scanning electron
microscopy (SEM), and thermo gravimetric analysis.
The corrosion performances of the sol–gel-coated
samples were investigated by electrochemical impedance
spectroscopy (EIS) and standard salt spray tests.
The hybrid coatings were found to be dense, more
uniform, and defect free. In addition, the coatings also
proved its excellent corrosion protection on phosphated
steel sheet.
Abstract: Titania-containing organic–inorganic hybrid sol–gel film was developed to improve the corrosion resistance
property of steel. Titania precursor was prepared from titanium-isopropoxide and methyl hydrogen silicone
was used as a coupling agent to enhance the adhesion and hydrophobic nature of coating. The kinetics,
thermal resistance and morphology of films were analyzed by, fourier transformed infrared spectroscopy,
thermo-gravimetric and differential thermal analysis and scanning electron microscopy. The anticorrosion
performance of the sol–gel coated sample was investigated by electrochemical impedance spectroscopy.
The results demonstrated that coatings were dense, uniform and provided excellent corrosion resistance
properties.
