Pankaj Chamoli; Malay K. Das; Kamal K. Kar
Abstract
In the present study, temperature dependence reduction of graphene oxide into graphene nanosheets has been demonstrated using green reducing agent, urea. As synthesized graphene nanosheets have been characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy(UV-Vis), ...
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In the present study, temperature dependence reduction of graphene oxide into graphene nanosheets has been demonstrated using green reducing agent, urea. As synthesized graphene nanosheets have been characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy(UV-Vis), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and X-ray photon spectroscopy (XPS). Raman analysis confirms that the maximum reduction of graphene oxide is observed at 140 o C, and reached to high Raman D to G band intensity ratio of ~ 1.41. FTIR analysis supports the Raman signature of maximum reduction of oxygen functional groups from graphene oxide at 140 o C. XPS analysis validates the Raman and FTIR signature of maximum removal of oxygen species from graphene oxide at 140 o C, and confirms the attainment of the C/O ratio of ~ 5.66. Result indicates that the urea offers excellent reductive ability at high temperature to produce graphene nanosheets.
Deepak Patil; Ajay Vasudeo Rane; K Kanny; Abitha V K; Anagha Sabnis
Abstract
Novel self-repairing Urea-Phenol-Formaldehyde (UPF) microcapsules containing linseed oil were prepared via in-situ polymerization in an oil-in-water emulsion. The main purpose of encapsulation is to control the release of linseed oil, when external conditions such as mechanical stress or energy cause ...
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Novel self-repairing Urea-Phenol-Formaldehyde (UPF) microcapsules containing linseed oil were prepared via in-situ polymerization in an oil-in-water emulsion. The main purpose of encapsulation is to control the release of linseed oil, when external conditions such as mechanical stress or energy cause microcapsules to break. These controlled release mechanisms of linseed oil make them suitable for application in self-healing coatings. Chemical structure analyses of microcapsules were studied by Fourier transform infrared spectroscopy (FTIR), optical microscopy and scanning electron microscopy for their structural & morphological illustrations. Controllable particle sizes were determined under optical microscope and as well using particle size analyzer. To determine the healing efficiency, the microcapsules, were incorporated in the epoxy coatings in varying proportions. The effects of the same on anti-corrosion performance was carried out in 5% NaCl aqueous solution (ASTM B117) and Decreasing trend of pencil hardness, scratch hardness, Impact resistance with the increase in concentration of microcapsules was observed. Chemical resistance could also be attributed to the presence of aromatic structures in epoxy which impart chemical stability. Secondary hydroxyl moiety in epoxy chain forms hydrogen bonding with the metal substrate that would contribute to good adhesive forces. Epoxy coatings incorporated with microcapsules showed better corrosion resistance than neat epoxy coating, where neat epoxy coating showed rust and spreading of rust observed on tested panel. Mechanical properties decreased on incorporating microcapsules into epoxy matrix, hence development of mechanical properties without effecting the corrosion properties shall be studied further.
Bhavani Prasad Nenavathu; Raj Kumar Dutta
Abstract
Semiconductor nanoparticles (NPs) have attracted much attention as a new class of fluorescent probe for many biological applications including biosensors for glucose, cholesterol, cysteine etc., which were based on their size dependent unique electrical and photophysical properties. One of the major ...
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Semiconductor nanoparticles (NPs) have attracted much attention as a new class of fluorescent probe for many biological applications including biosensors for glucose, cholesterol, cysteine etc., which were based on their size dependent unique electrical and photophysical properties. One of the major challenges in fabricating nanomaterial based biosensor is conjugation of a suitable compound to quantum dots which is preferably selective to the analyte of interest. Here we report our studies on synthesis, characterization and application of jack bean meal urease immobilized on CdS quantum dots (QDs) for sensing of urea. The CdS QDs were synthesized by chemical precipitation method using Mercaptoacetic acid (MAA) for controlling size as well as for imparting functional group for conjugating urease. The urease immobilize on MAA capped CdS nanoparticle was characterized by an array of techniques, like, UV- visible, Fluorescence, XRD, FT-IR and SEM EDAX. The detection capability of urea was studied by fluorescence spectroscopy at an excitation wavelength of λex = 430 nm and emission wavelength of λem= 546 nm. This method was capable to detect urea in the concentration range of 0.1 µM to 1 mM.