Papers by Ankita Hazarika
Nano Energy, 2021
ABSTRACT A low-power-consuming, self-powered wearable personal thermal management (PTM) device co... more ABSTRACT A low-power-consuming, self-powered wearable personal thermal management (PTM) device could minimize our reliability on external power sources. Herein, we describe the fabrication of a self-powered PTM device providing thermotherapy that can be wirelessly heated, with warmth preservation and heat produced via the triboelectric effect. Initially, ferromagnetic porous spongy FexCo1−xP nanostructures were synthesized uniformly over the surface of woven Kevlar fiber (WKF). Synthesized MXene was then dispersed in polydimethylsiloxane (PDMS) and prepared as a composite with WKF/FexCo1−xP. The combined effect of MXene and FexCo1−xP resulted in very effective Joule heating (74°C at 3 V), and the ferromagnetic behavior of the composite induced wireless heating. The dense interrelated porous structure created by MXene incorporation helped to maintain body warmth (an enhancement of 40.1% compared with bare WKF/PDMS) by reflecting almost all of the infrared radiation (97.7%) back to the body. The composite also exhibited high impact resistance (131.4% compared with WKF/PDMS) for use as smart body armor. Additionally, the PTM device exhibited a maximum power density of 1.3 mW cm−2 at a low impact frequency of 5 Hz and was capable of harvesting energy from human motion and wind, indicating a potential self-heating ability of the PTM composite.
Advanced Functional Materials
Chemical Engineering Journal
• CuCoSe nanowire grown WCF based structural supercapacitor was developed. • Device exhibited hig... more • CuCoSe nanowire grown WCF based structural supercapacitor was developed. • Device exhibited high electrochemical performance with brilliant cyclicability. • Polyester resin based electrolyte was developed with ionic liquid and Li-salt. • Excellent energy (191.64 mWhk g −1) and power densities (36.65 W kg −1) achieved. • At mechanical failure (481.29 MPa), 77.3% capacitance retention were recorded. A R T I C L E I N F O Keywords: Structural supercapacitor Multifunctionality Solid electrolyte Electrochemical performance Mechanical property A B S T R A C T Structural supercapacitors provide a variety of opportunities for woven carbon fibers in portable electronics, hybrid automobiles and aerospace applications. We describe herein the synthesis of bimetallic Cu-Co selenide nanowires based on woven carbon fibers, and their use as electrodes in supercapacitors. Woven Kevlar fiber is used as separator for the electrodes and a polyester resin with an ionic liquid and lithium salt is used as solid polymer electrolyte. The supercapacitors exhibit efficient energy storage and significant enhancements in mechanical strength (89.38%) and modulus (70.41%) over those of bare woven carbon fiber base supercapacitors. The specific capacitance of these supercapacitors increases from 0.197 F g −1 to 28.63 F g −1 after the growth of nanowires, with accordingly high energy density (191.64 mW h kg −1) and power density (36.65 W kg −1). In situ mechano-electrochemical tests of these supercapacitors yield excellent capacitance retention (77.3%) at the mechanical failure point (481.29 MPa).
Journal of Environmental Chemical Engineering
Composites Part B: Engineering
ACS applied materials & interfaces, Jan 18, 2017
Well-aligned NiCo2S4 nanowires, synthesized hydrothermally on the surface of woven Kevlar fiber (... more Well-aligned NiCo2S4 nanowires, synthesized hydrothermally on the surface of woven Kevlar fiber (WKF), were used to fabricate composites with reduced graphene oxide (rGO) dispersed in polyester resin (PES) by means of vacuum-assisted resin transfer molding. The NiCo2S4 nanowires were synthesized with three precursor concentrations. Nanowire growth was characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Hierarchical and high growth density of the nanowires led to exceptional mechanical properties of the composites. Compared with bare WKF/PES, the tensile strength and absorbed impact energy were enhanced by 96.2% and 92.3%, respectively, for WKF/NiCo2S4/rGO (1.5%)/PES. The synergistic effect of NiCo2S4 nanowires and rGO in the fabricated composites improved the electrical conductivity of insulating WKF/PES composites, reducing the resistance to ∼103 Ω. Joule heating performance depended strongly o...
Wood Material Science & Engineering
ABSTRACT Wood polymer nanocomposites (WPNCs) based on nano-ZnO and nanoclay were prepared by impr... more ABSTRACT Wood polymer nanocomposites (WPNCs) based on nano-ZnO and nanoclay were prepared by impregnation of melamine formaldehyde-furfuryl alcohol copolymer, 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU), a cross-linking agent and a renewable polymer obtained as a gum from the plant Moringa oleifera under vacuum condition. Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD) studies were employed for the characterization of modified ZnO and WPNCs. The change in crystallinity index (CrI) value of the cellulose in wood and the distribution of ZnO nanoparticles in composites were determined using FTIR and XRD. Scanning electron microscopy and Transmission electron microscopy showed the presence of nanoparticles and nanoclay in the cell lumen or cell wall of wood. An enhanced UV resistance property was shown by the treated wood samples as judged by lower weight loss, carbonyl index, lignin index, cellulose CrI values, and mechanical property loss compared to the untreated wood samples. Wood polymer composites treated with 3 phr each of nanoclay, ZnO, and the plant gum showed an improvement in mechanical properties, flame-retarding properties, thermal stability, and lower water uptake capacity.
Scientific Reports
We synthesized Ag nanoparticle-decorated multilayered graphene nanosheets (Ag-graphene) from grap... more We synthesized Ag nanoparticle-decorated multilayered graphene nanosheets (Ag-graphene) from graphite nanoplatelets and silver nitrate through 90-100 s of microwave exposure, without the use of any mineral acids or harsh reducing agents. Fe nanoparticle-decorated carbon nanotubes (Fe-CNTs) were grown on polypyrrole (PPy) deposited on woven Kevlar fibre (WKF), using ferrocene as a catalyst, under microwave irradiation. Fe-CNTs grown on WKF and Ag-graphene dispersed in polyester resin (PES) were combined to fabricate Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites by vacuumassisted resin transfer moulding. The combined effect of Fe-CNTs and Ag-graphene in the resulting composites resulted in a remarkable enhancement of tensile properties (a 192.56% increase in strength and 100.64% increase in modulus) as well as impact resistance (a 116.33% increase). The electrical conductivity significantly increased for Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites. The effectiveness of electromagnetic interference shielding, which relies strongly on the Ag-graphene content in the composites, was 25 times higher in Ag-graphene/Fe-CNT/PPy-coated WKF/PES than in neat WKF/PES composites. The current work offers a novel route for fabricating highly promising, cost effective WKF/PES composites through microwave-assisted synthesis of Fe-CNTs and Ag-graphene. As most electronics now-a-days are wireless, electromagnetic interference (EMI) has been receiving increasing attention due to its impact on EMI-sensitive electronic devices and telecommunication. Shielding of these unnecessary electromagnetic (EM) waves has become a big concern for many applications, including those in military and commercial sectors 1,2. The attenuation of EM waves can be achieved by reflection or absorption of received radiation 3. Generally, EM waves are shielded by means of conventional metal barriers, which possess drawbacks of increased weight, reduced flexibility, susceptibility to corrosion, and restricted effectiveness of tuning the EM radiation 4. Conductive polymer composites (CPCs) have gained attention due to their light weight, flexible design and corrosion-resistant properties 5,6. Carbon-based nano-sized filler materials such as carbon nanofibers (CNFs), graphite, carbon black (CB), and carbon nanotubes (CNTs) have been widely used in polymer composites for EMI shielding purposes, mechanical reinforcement as they have superior corrosion resistance, are electrically conductive and have low weight densities 7-9. CNTs, in particular are an excellent candidate to produce high-performance conductive composites that are required for EMI shielding, due to their high aspect ratio, surface area, excellent dielectric properties, high conductivity and superior mechanical properties 10,11. It is potential nano reinforcement in fiber-reinforced polymer composite that effectively helps to transfer load on application of stress. The high aspect ratio of multiwall carbon nanotubes (MWCNTs), for example, lowers their percolation threshold compared to metal nanoparticles, which results in a high electrical conductivity 12. However, the shielding mechanism by absorption is lacking, as magnetic dipoles are absent in MWCNTs. Therefore, the use of ferromagnetic compounds like Fe, Co, and Ni nanoparticles could be highly promising for EMI shielding. Physical mixing or decorating CNTs with such metal nanoparticles are two ways to form composites. However,
Composites Part A: Applied Science and Manufacturing
Novel structural supercapacitors based on CuO nanowires and woven carbon fiber (WCF) has been dev... more Novel structural supercapacitors based on CuO nanowires and woven carbon fiber (WCF) has been developed for the first time employing vacuum assisted resin transfer molding (VARTM) process. The growth of CuO nanowires on WCF is an efficient process and can be used in structural capacitors which can trigger the electric vehicle industries toward a new direction. The specific surface area of the carbon fiber was enhanced by NaOH etching (41.36 m 2 g À1) and by growing CuO nanowires (132.85 m 2 g À1) on the surface of the WCF. The specific capacitance of the CuO–WCF based supercapacitor was 2.48 F g À1 , compared with 0.16 F g À1 for the bare WCF-based supercapacitor. The usage of ionic liquid and lithium salt improved the capacitance to 5.40 and 6.75 F g À1 with lowest ESR and R p values of 133 and 1240 X along with improving mechanical properties within an acceptable range. The energy and power densities were also increased up to 106.04 mW h kg À1 and 12.57 W kg À1. Thus, this study demonstrated that growing CuO nanowires on the surface of WCF is a novel approach to improve multifunctionality that could be exploited in diverse applications such as electric cars, unmanned aerial vehicles (UAVs), and portable electronic devices.
Chemical Engineering Journal
Composites Science and Technology
International Journal of Energy Research
SUMMARY In the last decades, fuel scarcity and increasing pollution level pave the way for an ext... more SUMMARY In the last decades, fuel scarcity and increasing pollution level pave the way for an extensive interest in alternatives to petroleum-based fuels such as biodiesel, solar cells, lithium ion batteries, and supercapacitors. Among them, structural supercapacitors have been considered as promising candidates for automotive industries in present time. Herein, the use of carbon fiber-based supercapacitors in automotive applications is reviewed. Carbon fiber is an excellent candidate for vehicle body applications, and its composites could be widely used in the development of supercapacitors that could provide both structural and energy storage functions. Different surface modification processes of the carbon fiber electrode to enhance the electrochemical as well as mechanical performances are discussed. The advantages of the glass fiber separator and its comparison with other types of dielectric media have been incorporated. The synthesis procedures of the multifunc-tional solid polymer electrolyte and its significance have been also elaborated. The fabrication process, component selection , limitations, and future challenges of these supercapacitors are briefly assimilated in this review.
Composites Part A: Applied Science and Manufacturing, 2015
Composites Part A: Applied Science and Manufacturing, 2016
Journal of Bionic Engineering, 2015
ABSTRACT Melamine-formaldehyde acrylamide (MFA) copolymer was prepared and vacuum impregnated int... more ABSTRACT Melamine-formaldehyde acrylamide (MFA) copolymer was prepared and vacuum impregnated into wood in presence of 1,3-dimethylol 4,5-dihydroxyethylene urea (DMDHEU) as crosslinker, vinyltrichlorosilane (VTCS) modified montmorillonite (MMT) and Gum Polymer (GP) derived from Moringa oleifera as a flame retarding agent under catalyst heat treatment. The formation of MFA and DMDHEU was confirmed by Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR) studies. The crystallinity of the composites and interaction among them was studied by X-ray Diffrac-tometry (XRD) and FTIR study. Maximum interaction was found in wood samples treated with MFA/DMDHEU/GP (3 phr)/MMT as shown by FTIR. Scanning Electron Microscopy (SEM) revealed the presence of polymer and MMT in the composites. Transmission Electron Microscopy (TEM) study indicated the incorporation of MMT into the wood polymer composite. Thermal stability and flammability were checked by Thermogravimetric Analyser (TGA) and Limiting Oxygen Index (LOI) instrument. The treatment of wood with GP had a significant influence on the thermal stability and flame retardant properties of the composites. Remarkable improvement in water repellency and chemical resistance was found for the treated wood samples. The composites showed significant improvement in mechanical properties due to treatment.
Advanced Structured Materials, 2015
ABSTRACT Numerous studies are underway on the preparation and applications of petroleum-based pol... more ABSTRACT Numerous studies are underway on the preparation and applications of petroleum-based polymer nanocomposites. The depletion of world oil pool, non-biodegradability, and raising cost of petroleum-based materials are some of the disadvantages allied with these polymers-based products. The utilization of renewable materials has attracted researchers because of its easy availability and low cost. They can potentially remove the harmful effects of petroleum-based materials and thus show a greener path in the fields of application of composites. The biocomposites developed by using renewable polymers such as furfuryl alcohol, poly(lactic acid), gluten, starch, soy flour, etc., and naturally available fibers have been gaining considerable attention because of their environment-friendly nature. Wood is a biologically derived biodegradable raw material which requires minimum processing energy. Wood polymer composites (WPC) have tremendous advantageous properties and it rapidly improves the mechanical, physical, chemical as well as other properties of the composite suitable for different outdoor and indoor applications. The properties of the WPC can be improved to the desired level through the application of nanotechnology, cross-linking agents, flame retardants, grafting, etc. Nano-based wood polymer composite provides versatile advantages in their properties compared to the conventional WPC. Flame retardants obtained from renewable resource such as the gum of the plant Moringa oleifera can efficiently improve the flame retardancy along with other properties of the composites. This chapter discusses the various properties of renewable polymer-based wood polymer nanocomposites as a potential, sustainable, green composite to attain durability without using harmful chemicals.
Defence science journal
Wood is a unique and renewable resource material that has been an important substance since time ... more Wood is a unique and renewable resource material that has been an important substance since time immemorial of human civilization because of its easy availability unique aesthetic look and useful properties 1. It can be reaped sustainably at a constant rate without depleting the existing resource pool. Because of the influence of increasing human activities on the environment, awareness of the society on the environment is rapidly increasing, thus environmental considerations have given due attention to effect a change in the way of utilization of materials for various purposes. Thus, chemical industries are seeking to manufacture products with minimal environmental impact. Scientists have been working to improve the utilization of raw material, reduce production inefficiencies and develop more sustainable industrial practices. The widespread occurrence, stability, hardness, lightness, elasticity and as perspective potential renewable material make wood an important raw material sources 2. Natural look and versatility make wood a class of material for various purposes of applications. It has wide range of applications to make items like paper, pulp, construction of materials and as resource material for energy generation 3. Wood is a natural polymeric composite consisting of cellulose, hemicelluloses and phenolic polymers of lignin. The cellulose is a polymer of D-glucopyranose units linked together by β(1→4) glycosidic bonds. Hemicelluloses are heteropolysaccharides having a lower degree of polymerization (DP) than cellulose of about 100-300. Cellulose is more ordered than hemicellulose, although some hemicellulose can form crystalline units. Water present in atmospheric moisture can easily form hydrogen bonding with the free hydroxyl groups in cellulose resulting in shrinking and swelling of wood depending upon its moisture content. Lignins have the least water sorption tendency and are amorphous, highly complex, mainly aromatic, polymers of phenylpropane units 4. Lignin is associated with hemicelluloses through covalent bond forming lignin-carbohydrate complexes but there is no evidence of their association with cellulose. Thus, the hydroxyl groups present in the cell wall of wood are the most abundant reactive and vulnerable chemical site 3. Mechanical anisotropy arises in wood due to its highly heterogeneous structure. Among the numerous applications, the utilization of wood in particular for flooring and hard wearing wood surfaces preferably need an improvement of strength and elasticity in the direction normal to the grain. Hence strength in lateral direction is most desirable. The success of trees as
Polymer Engineering & Science, 2014
ABSTRACT Wood polymer composites (WPC) based on nano SiO2 and nanoclay were prepared by the impre... more ABSTRACT Wood polymer composites (WPC) based on nano SiO2 and nanoclay were prepared by the impregnation of melamine formaldehyde-furfuryl alcohol copolymer, 1,3-dimethylol 4,5-dihydroxy ethylene urea, a crosslinking agent, and a renewable polymer. Surface modification of SiO2 and formation of composites were characterized by Fourier Transform Infrared Spectroscopy (FTIR). X-ray diffractometry (XRD) studies indicated a decrease in crystallinity of the composites. The crystallinity index value of wood cellulose decreased from 63.8 to 30.8 as determined from FTIR and XRD studies. Scanning Electron Microscopy was used for morphological characterization. Transmission Electron Microscopy (TEM) showed uniform distribution of nano SiO2 and nanoclay in the composites. Remarkable reduction in water uptake capacity was observed for the treated wood samples. It was found to reduce from 142.2% to 30.2%. Both tensile and flexural properties increased upto 76.5% and 23.6%, respectively in the WPCs. An improvement in chemical resistance, flame retardancy and thermal stability were observed in the composites as a result of treatment. POLYM. ENG. SCI., 54:1019–1029, 2014. © 2013 Society of Plastics Engineers
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Papers by Ankita Hazarika