Journal Articles
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Item Defence applications of polymer nanocomposites(Defense Scientific Information and Documentation Centre, 2010) Kurahatti, R.V.; Surendranathan, A.O.; Kori, S.A.; Singh, N.; Kumar, A.V.R.; Srivastava, S.The potential opportunities promised by nanotechnology for enabling advances in defence technologies are staggering. Although these opportunities are likely to be realised over a few decades, many advantages are currently being explored, particularly for defence applications. This review provides an insight into the capabilities offered by nanocomposites which include smart materials, harder/lighter platforms, new fuel sources and storage as well as novel medical applications. It discusses polymer-based nanocomposite materials, nanoscale fillers and provides examples of the actual and potential uses of nanocomposite materials in defence with practical examples. © 2010, DESIDOC.Item Ultrasound assisted synthesis of polymer nanocomposites: a review(Springer Science and Business Media B.V., 2023) Soman, V.; Vishwakarma, K.; Poddar, M.K.The potential of ultrasonication as a technique to enhance the production of polymer nanocomposites is examined in this review paper. Polymer nanocomposites have been widely employed in recent years because of their remarkable mechanical, electrical, and optical properties. The article focuses on the application of several synthesis techniques, including solvent casting, 3D printing, electrospinning, and template synthesis. It has been established that uniformly dispersing nanoparticles inside the polymer matrix during ultrasonication can greatly improve the quality of nanocomposites. Recent research has shown that nanocomposites made using ultrasonication have improved mechanical and thermal stability. However, scaling up these techniques remains a challenge and requires further research. © 2023, The Polymer Society, Taipei.Item Nano ZnO-activated carbon composite electrodes for supercapacitors(2010) Muthu, M.S.; Bhat, D.K.; Aggarwal, A.; Prahladh Iyer, S.; Sravani, G.A symmetrical (p/p) supercapacitor has been fabricated by making use of nanostructured zinc oxide (ZnO)-activated carbon (AC) composite electrodes for the first time. The composites have been characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction analysis (XRD). Electrochemical properties of the prepared nanocomposite electrodes and the supercapacitor have been studied using cyclic voltammetry (CV) and AC impedance spectroscopy in 0.1 M Na2SO4 as electrolyte. The ZnO-AC nanocomposite electrode showed a specific capacitance of 160 F/g for 1:1 composition. The specific capacitance of the electrodes decreased with increase in zinc oxide content. Galvanostatic charge-discharge measurements have been done at various current densities, namely 2, 4, 6 and 7 mA/cm2. It has been found that the cells have excellent electrochemical reversibility and capacitive characteristics in 0.1 M Na2SO4 electrolyte. It has also been observed that the specific capacitance is constant up to 500 cycles at all current densities. © 2010 Elsevier B.V. All rights reserved.Item Synthesis and third order optical nonlinearity studies of the donor-acceptor conjugated polymer, poly(2-[3,4-didodecyloxy-5-(1,3,4-oxadiazol- 2-yl)thiophen-2-yl]-5-phenyl-1,3,4-oxadiazole) and a polymer/TiO2 nanocomposite(2010) Murali, M.G.; Ramya, M.G.; Udayakumar, D.; Lakshmi, N.B.; Philip, R.A donor-acceptor conjugated polymer (PDOThPOD) containing 3,4-didodecyloxythiophene and (1,3,4-oxadiazolyl)benzene units is synthesized by using precursor polyhydrazide route. Cyclic voltammetry studies reveal that the polymer possesses a low-lying LUMO energy level (-3.57 eV). A nanocomposite of polymer PDOThPOD and nano TiO2 is also prepared. The linear optical properties of PDOThPOD and the nanocomposite are studied using UV-vis absorption spectroscopy and fluorescence emission spectroscopy. z-scan technique is used to study the third order nonlinear optical properties of the polymer and nanocomposite films. Both polymer and nanocomposite films show a strong optical limiting behavior. The value of nonlinear absorption coefficient (?) is found to be of the order of 10-7 m/W, indicating that these materials are potentially suited for fabricating optical limiters. © 2010 Elsevier B.V. All rights reserved.Item Crystallinity, conductivity, and magnetic properties of PVDF-Fe 3O4 composite films(2011) Bhatt, A.S.; Bhat, D.K.; Santosh, M.S.The formation of Fe3O4 nanoparticles by hydrothermal process has been studied. X-ray Diffraction measurements were carried out to distinguish between the phases formed during the synthesis. Using the synthesized Fe3O4 nanoparticles, poly(vinyledene fluoride)-Fe3O4 composite films were prepared by spin coating method. Scanning electron microscopy of the composite films showed the presence of Fe3O4 nanoparticles in the form of aggregates on the surface and inside of the porous polymer matrix. Differential Scanning calorimetry revealed that the crystallinity of PVDF decreased with the addition of Fe3O4. The conductitivity of the composite films was strongly influenced by the Fe3O4 content; conductivity increased with increase in Fe3O4 content. Vibration sample magnetometry results revealed the ferromagnetic behavior of the synthesized iron oxide nanoparticles with a Ms value of 74.50 emu/g. Also the presence of Fe3O4 nanoparticles rendered the composite films magnetic. © 2010 Wiley Periodicals, Inc.Item Role of zirconia filler on friction and dry sliding wear behaviour of bismaleimide nanocomposites(2011) Kurahatti, R.V.; Surendranathan, A.O.; Srivastava, S.; Singh, N.; Ramesh Kumar, A.V.; Suresha, B.This paper discusses the friction and dry sliding wear behaviour of nano-zirconia (nano-ZrO2) filled bismleimide (BMI) composites. Nano-ZrO2 filled BMI composites, containing 0.5, 1, 5 and 10wt.% were prepared using high shear mixer. The influence of these particles on the microhardness, friction and dry sliding wear behaviour were measured with microhardness tester and pin-on-disc wear apparatus. The experimental results indicated that the frictional coefficient and specific wear rate of BMI can be reduced at rather low concentration of nano-ZrO2. The lowest specific wear rate of 4×10-6mm3/Nm was observed for 5wt.% nano-ZrO2 filled composite which is decreased by 78% as compared to the neat BMI. The incorporation of nano-ZrO2 particles leads to an increased hardness of BMI and wear performance of the composites shows good correlation with the hardness up to 5wt.% of filler loading. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms. © 2011 Elsevier Ltd.Item Friction and dry sliding wear behaviour of Ni filled epoxy nanocomposite(2011) Kurahatti, R.V.; Suredranathan, A.O.; Kori, S.A.; Ramesh Kumar, A.V.; Mordina, B.; Mallapur, D.G.Nanosized metal particle filled polymer composites are finding numerous tribological applications in recent years. In the present work, the matrix properties were investigated by introducing nickel nanoparticles (60-100 nm, filler content of 0?5-10 wt-%) into epoxy resin. The influence of these particles on friction and dry sliding wear behaviour was measured using a pin on disc wear set-up. The experimental results indicated that the coefficient of friction and the specific wear rate of epoxy resin can be reduced with a rather low weight fraction of Ni particles. The lowest specific wear rate of 0?6461024 mm3 N21 m21 (compared to neat resin's value of 2?261024 mm3 N21 m21) was observed for composites with the filler content of 0?5 wt-%. The reinforcement of Ni particles leads to improved mechanical properties of the epoxy composites. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms. © 2011 W. S. Maney & Son Ltd.Item Electrochemical properties of chitosan-Co3O4 nanocomposite films(Elsevier B.V., 2011) Bhatt, A.S.; Bhat, D.K.; Santosh, M.S.Chitosan-Co3O4 composite films have been prepared by solution casting method. The obtained films have been characterised by XRD and FESEM. The electrical properties of the films are examined by impedance spectroscopy in the temperature range 303-343 K. The impedance plot of the films pronounces the role of temperature in charge-transfer resistance of the composite. Frequency as well as temperature dependencies of dielectric constant and dielectric loss exhibit the general trend followed by carrier dominated dielectrics. Electric modulus parameters give an insight on the ionic conductivity and relaxation phenomena of the composite films. The dielectric parameters along with modulus data have been exploited to discuss the conduction mechanism in the material. The minimum activation energy of 3.9 kJ mol -1 and maximum room temperature conductivity of 1.94 × 10 -2 S cm-1 were found for composite film with 8% Co 3O4 content. © 2011 Elsevier B.V. All rights reserved.Item Chitosan/NiO nanocomposites: A potential new dielectric material(2011) Bhatt, A.S.; Bhat, D.K.; Santosh, M.S.; Tai, C.-W.The study of electrochemical behavior of organic-inorganic nanocomposite materials remains a major challenge for application in energy storage devices. Here, new composite materials of chitosan and NiO nanoparticles have been fabricated. The NiO nanoparticles are well characterized by infrared spectroscopy, X-ray diffraction and transmission electron microscopy. The electrical properties of the films are studied by impedance spectroscopy at different temperatures; and thereby permittivity, electric modulus and conductivity data are obtained. By studying the variations in permittivity and electric modulus spectra with respect to applied frequency signal and temperature, the ionic conductivity of the material is investigated. The Correlated Barrier Hopping model is employed to understand the conduction mechanism. An admirable conductivity of 1.4 × 10-2 S cm -1 is obtained for a nanocomposite with 4 wt% NiO content. The activation energies of the composite films decrease with increase in NiO content, from 16.5 to 4.8 kJ mol-1. © 2011 The Royal Society of Chemistry.Item Characterization of poly(ethylene-co-vinyl acetate-co-carbon monoxide)/layered silicate clay hybrids obtained by melt mixing(2011) Anandhan, S.; Patil, H.G.; Babu, R.R.In recent times, polymer-layered silicate nanocomposites have drawn a great deal of attention because they often exhibit tremendous improvements in material properties compared with virgin polymers or conventional microor macro-composites. In the present study, nanocomposites were developed from organically modified clay and poly(ethylene-co-vinyl acetate-co-carbon monoxide) by melt mixing. FTIR spectroscopy reveals that the interaction between the organoclay and EVACO is thermodynamically favored. High resolution wide angle X-ray diffraction and transmission electron microscopy were used to study the morphology of the nanocomposites. Elemental mapping by scanning electron microscopy indicates good dispersion and distribution of the nanoclay in EVACO matrix. The mechanical properties of the nanocomposites are optimum at a clay loading of 3%. © Springer Science+Business Media, LLC 2011.