Physical effects of nanoaluminum oxide and nanographene on kenaf epoxy composite; vacuum bagging process

In this study, the effect of secondary filler nanographene and primary filler nanoaluminum oxide with kenaf epoxy was investigated. The vacuum bagging process was performed, and a magnetic stirrer was used for blending additives. Water absorption (borewell, distilled, normal, and seawater) and chemical absorption (acid, base, and neutral solution) tests were carried out to evaluate the water absorption, chemical absorption, thickness swelling, and diffusivity of the composite with varying percentages of fillers. The result demonstrates that the addition of 6% primary and 3% secondary filler together, increases the density of the sample by 13.5% and decreases void content by 77%. The addition of secondary filler lowers water absorption in normal water by 1.3% compared to other types of water, as the addition of secondary filler increases the water absorption decreases by 70% in borewell water, 75% in distilled water, 76% in normal water, and 69% in seawater. Thickness swelling of the samples decreases upon the addition of secondary fillers. In acid, the primary and secondary fillers increase the resistance to dissolution. The diffusivity rate of the sample with a combination of fillers 1.3 × 10⁻⁵.     

One-pot hydrothermal synthesis of Cu2Te/NiTe nanocomposite materials: A structural,morphological, and optical study

Due to various structural and optical properties, metal chalcogenide nanomaterials are favorable candidates for different optoelectronic applications. In the current report, Cu₂Te/NiTe nanocomposites were synthesized via the facile hydrothermal method. With the variation of concentration of Cu and Ni, various materials had been prepared along with pure Cu₂Te and NiTe. The observed several vibrational modes in the material through the Raman spectroscopy are well agreed with the appearing phases. The morphological study confirmed the nanostructures are combination of nanoparticles with sheets. The size of nanoparticles varied in the range of 66–34 nm. The absorbance spectra of the nanocomposite exhibit a blueshift and support the enhancement in the optical bandgap. The value of bandgap energy of the composite samples has been noted in the range of 1.8–2.2 eV. This bandgap range enables the material for various optoelectronic applications such as solar cell and other photovoltaic devices. Thermal analysis of the material demonstrates the presences of several endothermic and exothermic peaks. Thus, several studies on the material prevail its various applicability as optoelectronics as well as other thermal application.     

Kinetic study of Hg(II)-promoted substitution of cyanide from hexacyanoferrate(II) in an anionic surfactant medium by 2,2′-bipyridine

The kinetic investigation of Hg(II)-promoted reaction between [Fe(CN)₆]⁴⁻ and 2,2′-bipyridine (Bipy) has been performed in anionic sodium dodecyl sulfate (SDS) micellar medium by recording the surge in absorbance at 400 nm, corresponding to ultimate reaction product [Fe(CN)₄ Bipy]²⁻ using UV–visible spectrophotometer. Pseudo-first-order condition has been used to examine the progress of reaction as a function of temperature, [Fe(CN)₆⁴⁻], ionic strength, [SDS], pH, [Hg²⁺], and [Bipy] by changing one parameter at a time. The results exhibit that [Hg²⁺], [SDS], and pH are the decisive parameter showing maximum reaction rate at 1.5 × 10⁻⁴ mol dm⁻³, 6.0 × 10⁻³ mol dm⁻³, and 3.8, respectively. [Fe(CN)₆]⁴⁻ does not show any appreciable effect on the critical micellar concentration (CMC) of SDS as the polar head of SDS and [Fe(CN)₆]⁴⁻ both are negatively charged. Variable order kinetics was observed for [Fe(CN)₆]⁴⁻ and Bipy in their examined concentration range. The reverse response observed in the reaction rate with [KNO₃] shows a negative salt effect. The K⁺ provided by K₄[Fe(CN)₆] and KNO₃ decreases the repulsion between the negatively charged heads of the surfactant molecules thereby decreasing the CMC of SDS. The negative value for the entropy of activation also supports the interchange dissociative (I_d) mechanism recommended by us.