1. Journal Articles
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Item Use of nano-ATH as a multi-functional additive for poly(ethylene-co-vinyl acetate-co-carbon monoxide)(2014) George, G.; Mahendran, A.; Anandhan, S.Flame retardant aluminum hydroxide (ATH) nanoparticles of size ?10-20 nm were dispersed in ethylene-vinyl acetate-carbon monoxide terpolymer (EVACO) via solution casting. The effect of filler loading on the crystallizability, thermal, mechanical, flammability, optical and electrical properties of EVACO was evaluated. At 1 % filler loading nano-ATH particles exhibited very good dispersibility in the EVACO matrix and the % crystallinity of EVACO is the highest at this filler loading. The changes in crystallinity were studied by X-ray diffractometry and differential scanning calorimetry. The highest tensile strength was observed for the composite with 1 % nano-ATH loading, which has the best filler dispersion, and the decay in the tensile properties at higher filler loading is due to agglomerations of ATH nanoparticles and polymer-filler interface debonding. The UV absorption of these composites is augmented irrespective of the nano-ATH loading and ATH emerges as a good absorber of UV light. The DC electrical conductivity study of the composites proves that the addition nano-ATH is an efficient way to improve the dielectric properties of EVACO. The presence of nano-ATH improves the flame retardance of these composites. � 2014 Springer-Verlag Berlin Heidelberg.Item Tuning characteristics of Co3O4 nanofiber mats developed for electrochemical sensing of glucose and H2O2(2016) George, G.; Anandhan, S.Nano-crystalline Co3O4 nanofibrous mats were fabricated by calcining the precursor nanofibers obtained by electrospinning of a sol comprising of a unique polymeric binder poly(2-ethyl-2-oxazoline) and cobalt acetate tetrahydrate in water. The influence of the calcination temperature used for the synthesis of the oxide nanofibers from the xerogel fibers on various physico-chemical properties of the former was studied. The Co3O4 nanofibers obtained at 400 �C had the highest electrochemical sensitivity towards glucose and H2O2. Further, the results prove that Co3O4 nanofibers can be used for the detection of glucose and H2O2 concurrently as the response times taken by these moieties are different. Therefore, one can differentiate the concentration of glucose and H2O2 by analyzing the signals obtained after the respective response time and this multiple sensitivity of Co3O4 can be applied in the field of biosensors. � 2016 Elsevier B.V.Item Tribology and Mechanical Properties of Carbon Fabric/MWCNT/Epoxy Composites(2018) Shivamurthy, B.; Murthy, K.; Anandhan, S.Cryogenic treated multilayered carbon fabric/oxidized multiwall carbon nanotube/epoxy (CCF/O-MWCNT/E) composite and untreated carbon fabric/epoxy (CF/E) composite were prepared by hot compression molding technique. The density and mechanical properties such as tensile properties, flexural properties, interlaminar shear strength, and microhardness of the composites were investigated as per ASTM standards. The wear and coefficient of friction behavior were investigated using computer interfaced pin-on-disc test rig at room temperature for varied load and sliding speed. The morphology of worn surfaces of the wear test composite specimens were studied by scanning electron microscope. It is found that the synergetic effect of addition of O-MWCNT to epoxy matrix and cryogenic treatment of carbon fabric improved the wear resistance and mechanical properties. Also, a thin lubricating film developed by the oxidized multiwall carbon nanotube/epoxy wear debris reduces the coefficient of sliding friction and wear rate. � 2018 B. Shivamurthy et al.Item Some new observations on the structural and phase evolution of nickel titanate nanofibers(2017) Kumar, B.S.; Shanmugharaj, A.M.; Kalpathy, S.K.; Anandhan, S.In this study, we report for the first time the synthesis of nickel titanate (NTO) nanofibers containing a mixture of ilmenite and spinel phases of NTO, at an atypical low temperature. Precursor nanofibers produced by sol-gel electrospinning were calcined at three different temperatures to produce the NTO nanofibers. Thermal analysis along with X-ray photoelectron spectroscopy confirmed the formation of non-crystalline stable phases of TiN and Ti-O-N that restrained the formation of ilmenite NTO, and the Ni-rich environment pushed the Ti atoms to tetrahedral sites to form a defective spinel structure. The crystallite size of spinel NTO was observed to increase as a function of the calcination temperature above 700 C, as the activation energy for coalescence and growth of spinel NTO was favorable. NTO nanofibers obtained above the calcination temperature of 700 C exhibited new band gap energy around 2.5 eV in Tauc plot. Oxygen vacancies in these ceramic nanofibers decreased as the calcination temperature was increased. A hypsochromic shift of 20 nm in the photoluminescence spectra suggested that the material had a Ni2+ rich NTO (spinel). 2017 Elsevier Ltd and Techna Group S.r.l.Item Solution electrospinning of styrene-acrylonitrile random copolymer from dimethyl sulfoxide(2013) Senthil, T.; Anandhan, S.Electrospinning is an efficient and versatile technique for the fabrication of ultrafine fibers having diameters ranging from nano to sub-micron level for various potential applications. In this study, we have investigated the influence of process and solution parameters, such as solution concentration, flow rate and applied voltage, on the morphology of electrospun poly(styrene-co-acrylonitrile) (SAN) fibers. Morphology and average diameter (Davg.) of the electrospun SAN fibers were characterized by scanning electron microscopy (SEM). The SEM results reveal that concentration, applied voltage and flow rate of solution are strongly associated with formation of defects, such as beads, in the fibers. Ultrafine SAN fibers with Davg. in the range of 96-872 nm were obtained by controlling the experimental parameters. The Davg. of electrospun fibers increased with increasing solution concentration, applied voltage and flow rate. Also, the Davg. exhibits a power law relationship with the solution concentration. 2013 Central Institute of Plastics Engineering & Technology.Item Thermoplastic vulcanizates from post consumer computer plastics/nitrile rubber blends by dynamic vulcanization(2013) Anandhan, S.; Bhowmick, A.K.Due to depletion of natural resources and increasing greenhouse emissions, new technologies for the transformation of waste polymers into valuable materials represent one of our greatest current needs. Acrylonitrile-butadiene-styrene terpolymer (ABS) is one of the most widely used engineering plastics and is used as outer casing for electronic equipment. Nitrile rubber (NBR) is used in many applications that demand oil resistance. In an attempt to explore whether these materials can be successfully recycled, we prepared blends of scrap computer plastics (SCP) based on ABS with NBR and waste NBR powder (w-NBR), and investigated their mechanical properties and recyclability. Specifically, we assessed the effect of dynamic vulcanization and replacement of virgin NBR with w-NBR on the properties of 60/40, 70/30, and 80/20 NBR/SCP blends. These blends exhibited thermoplastic elastomeric behavior. The thermoplastic elastomeric blends showed excellent swelling resistance to standard lubricant oil (namely, IRM 903 oil). 2013 Springer Japan.Item Thermodynamic miscibility and thermal and mechanical properties of poly(ethylene-co-vinyl acetate-co-carbon monoxide)/poly(vinyl chloride) blends(2015) Selvakumar, M.; Mahendran, A.; Bhagabati, P.; Anandhan, S.This paper reports the miscibility and thermal and mechanical properties of solution cast binary blends of poly(ethylene-co-vinyl acetate-co-carbon monoxide) (EVACO) and poly(vinyl chloride) (PVC). The composition of these blends was varied from 10:90 to 90:10 of PVC/EVACO (w/w %). Fourier transform infrared spectroscopy revealed an extensive intermolecular attraction between the blend components, which accounts for their mutual solubility. The differential scanning calorimetry study revealed that the blend components are miscible with each other in all proportions as they exhibited a single glass transition temperature. Tensile strength, moduli, and thermal stabilities of these blends significantly improved with increasing proportion of PVC. 2014 Wiley Periodicals, Inc.Item Sol-gel electrospun ZnMn2O4 nanofibers as bifunctional electrocatalysts for hydrogen and oxygen evolution reactions(2019) Shamitha, C.; Shetty, A.R.; Hegde, A.C.; Anandhan, S.Electrochemical water-splitting has gained significant attention for the development of next generation fuels. The present work is an investigation on the electrocatalytic activity towards both Oxygen Evolution Reaction (OER) and Hydrogen Evolution Reaction (HER) of ZnMn2O4 (ZMO) nanofabrics synthesized by sol-gel electrospinning followed by calcination (at 500, 600 and 700 C). Poly(styrene-co-acrylonitrile) was used as the polymeric binder for the production of nanofabrics. The morphological features of ZMO nanofabrics were studied by scanning electron microscopy and field emission scanning electron microscopy. The electrocatalytic behavior of ZMO nanofabrics obtained at different calcination temperatures was evaluated using chrono-potentiometry, cyclic voltammetry, and linear sweep voltammetry in an alkaline medium (1 M KOH). The ZMO nanofabrics calcined at 500 C exhibited the maximum electrocatalytic activity towards HER. This can be ascribed to their superior specific surface area (79.5 m2 g-1). The nanofabrics calcined at 700 C displayed the least potential for O2 evolution and hence they are considered to be effective for OER. The results prove that ZMO nanofabrics are promising candidates as bifunctional electrocatalysts for water-splitting applications. 2019 IOP Publishing Ltd.Item Sol gel electrospun mesoporous ZnMn2O4 nanofibers with superior specific surface area(2017) Shamitha, C.; Senthil, T.; Wu, L.; Kumar, B.S.; Anandhan, S.ZnMn2O4 has application potential in lithium ion batteries, supercapacitors, sensors, and thermistors. In this study, mesoporous spinel ZnMn2O4 nanofibers were synthesized by sol gel assisted electrospinning combined with calcination, using poly(styrene-co-acrylonitrile) as sacrificial polymeric binder. Structural, morphological and optical properties of these ceramic nanofibers were characterized. X-ray diffraction and X-ray photoelectron spectroscopy results revealed the presence of hexagonal ZnMnO3 and MnO phases in the ZnMn2O4 nanofibers produced. Based on these observations we propose a plausible mechanism of formation of ZnMn2O4 nanofibers. The nanofibers calcined at 773 K exhibit a specific surface area of 79.5 m2 g?1, which is higher than that of the zinc manganite nanofibers synthesized hitherto by sol gel electrospinning. Moreover, this material exhibits four bandgaps, which is believed to be the first observation in ZnMn2O4 nanofibers. 2017, Springer Science+Business Media, LLC.Item Synthesis and characterisation of nickel oxide nanofibre webs with alcohol sensing characteristics(2014) George, G.; Anandhan, S.In this study, nickel oxide (NiO) nanofibres were obtained by a sol-gel electrospinning process followed by calcination from an aqueous sol of poly(2-ethyl-2-oxazoline)/nickel acetate tetrahydrate. Thermogravimetric analysis was used to determine the degradation temperature of the composite fibres, so as to get nickel oxide nanofibres. X-ray photoelectron spectroscopy and X-ray diffraction studies revealed the complete elimination of the organic phase from NiO fibres during calcination. The change in grain size with calcination temperature was determined by X-ray diffraction. The defects in fibres resulted in the modification of their Raman spectra as compared with that of a single crystal. The magnetic properties of the fibres were reduced as the calcination temperature was increased; this is due to the presence of non-stoichiometric defects. As the calcination temperature was increased, the amount of defects was reduced, which induced a difference in the band gap energy of the fibres. Sensitivity of the NiO fibres towards five different alcohols was studied, and the sensitivity towards ethanol was the highest. The Royal Society of Chemistry 2014.