Soumya Mondal

Bio: Soumya Mondal is an academic researcher from Indian Institute of Technology Kharagpur. The author has contributed to research in topics: Graphene & Carbon black. The author has an hindex of 8, co-authored 11 publications receiving 197 citations. Previous affiliations of Soumya Mondal include University of Calcutta.

Synthesis and characterization of graphene from waste dry cell battery for electronic applications

Abstract: This study demonstrates the electronic applications of graphene synthesized from the graphite electrode of waste dry cell zinc–carbon batteries. Graphite powder [G (R)] is successfully recovered from the graphite electrode of waste batteries by acid treatment and used as starting material for synthesis of graphene oxide (GO) following Hummers method. Finally, reduced graphene oxide (RGO) was obtained from the chemical reduction of GO by hydrazine hydrate. RGO thus obtained was characterized by X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, UV-vis absorption spectroscopy, dynamic light scattering, energy dispersive X-ray spectra and transmission electron microscopy to get detailed information about the structure and morphology of the RGO. All the above characterization results confirmed the restoration of sp2 conjugation and removal of functional groups after the reduction of GO and also the sheet like morphology of RGO. The surface charge and stability of RGO in an aqueous medium are examined by measuring zeta potential. An electrochemical study demonstrated that, at different sweep rates, the current is the highest for RGO and lowest for GO and the current increases with an increasing sweep rate for all materials. The loop area of all the samples at the 100 mV s−1 sweep rate is the highest. The galvanostatic charging/discharging measurements have also been performed for both the GO and RGO samples at a current density of 1 mA g−1. Electro-conductivity measurement shows that RGO has higher conductivity than GO due to the restoration of the sp2 structure. The current voltage (I–V) characteristics show a non-linear behavior of GO and the ohmic nature of RGO.

Physical and electrochemical characterization of reduced graphene oxide/silver nanocomposites synthesized by adopting a green approach

Abstract: This study demonstrates the physical and electrochemical characterization of nanocomposites based on reduced graphene oxide (RGO) and silver nanoparticles (Ag NPs) synthesized by adopting a green and low cost approach using lactulose as a reducing and stabilizing agent. The RGO/Ag nanocomposites were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, UV-vis absorption spectroscopy and transmission electron microscopy (TEM) to obtain clear information about the removal of functional groups and morphology of nanocomposites. XRD results confirmed the formation of a high purity crystal of Ag on RGO. FTIR results established partial reduction of GO to RGO by lactulose. TEM images show that spherical Ag NPs of an average size of 4 nm are uniformly deposited onto RGO sheets and also prevent the restacking of RGO layers. The energy dispersive X-ray spectra (EDX) of RGO/Ag nanocomposites indicate the presence of Ag and graphene. Also, EDX spectra of FESEM show that Ag content increases with the increasing concentration of AgNO3 in RGO/Ag nanocomposites. The surface charge as well as stability of the nanocomposites is examined by measuring the zeta potential while electro-conductivity is measured by potentiostat–galvanostat. The zeta potential and conductivity of RGO/Ag nanocomposites is greatly improved compared to GO and RGO. The electro-conductivity of RGO/Ag nanocomposites indicates that conductivity of RGO/Ag nanocomposite increases with increasing concentration of Ag. The electrochemical result also indicates the presence of a higher amount of ionic functional groups in GO than those in RGO and RGO/Ag nanocomposites. GO indicates the lowest current which gradually increased for RGO and RGO/Ag nanocomposites, respectively.

Elastomer reinforcement by graphene nanoplatelets and synergistic improvements of electrical and mechanical properties of composites by hybrid nano fillers of graphene-carbon black & graphene-MWCNT

Abstract: Present work deals with the reinforcement behaviour of graphene nanoplatelets (GNP) in elastomer matrix of acrylonitrile butadiene (NBR) co-polymer. The addition of 20 phr GNP in NBR matrix a significant improvement in tensile strength (∼528%), and elongation at break (∼60%) compared to neat NBR is observed. Hybrid composites of NBR filled with GNP-CB and GNP-MWCNT at judicious proportion exhibit further improvement in the mentioned properties compared to those exhibited by composites containing individual fillers at same loading. This reflects strong synergistic effect on properties by hybrid fillers. Morphological studies reveal the state of dispersion of filler in matrix polymer, and this can be correlated with property improvements. The better synergistic effect of GNP-CB hybrid filler in comparison to GNP-MWCNT for improvement in mechanical and electrical properties as well as thermal stability may be attributed to the better filler dispersion and higher polymer-filler interaction for NBR-GNP-CB hybrid system compared to NBR-GNP-MWCNT system.

Maleic Anhydride Grafted Atactic Polypropylene As Exciting New Compatibilizer for poly(Ethylene-co-Octene) Organically Modified Clay Nanocomposites: Investigations on Mechanical and Rheological Properties

Abstract: This is probably the first report on maleic anhydride (MA) grafted atactic polypropylene (aPP) acting as a typical compatibilizer for synthesis of poly(ethylene-co-octene) (POE) organically modified montmorillonite (OMMT) nanocomposites. The maximally grafted aPP (93.67% with 3 wt % MA) was used for compatibilization. OMMT concentrations were varied as 1, 3, and 5 wt % with respect to POE. Only moderate improvements in mechanical and rheological properties were recorded in both uncompatibilized (POE–OMMT) and compatibilized (POE–OMMT–1 wt % compatibilizer) nanocomposites due to predominant aggregation of OMMT layers. However, at higher compatibilizer content, e.g. 3 and 5 wt %, similar properties were hugely improved (92% rise in tensile strength, 55% rise in net elongation, etc.) due to partial delamination of OMMT galleries. Better processability including reduced die swell and flow activation energy and smoother extrudate profiles were also obtained as additional benefits at those compositions due to o...

Graphene and its sensor-based applications: A review

Abstract: This paper presents an overview of the work done on graphene in recent years. It explains the preparation techniques, the properties of graphene related to its physio-chemical structure and some key applications. Graphene, due to its outstanding electrical, mechanical and thermal properties, has been one of the most popular choices to develop the electrodes of a sensor. It has been used in different forms including nanoparticle and oxide forms. Along with the preparation and properties of graphene, the categorization of the applications has been done based on the type of sensors. Comparisons between different research studies for each type have been made to highlight their performances. The challenges faced by the current graphene-based sensors along with some of the probable solutions and their future opportunities are also briefly explained in this paper.

A review of the electrical and mechanical properties of carbon nanofiller-reinforced polymer composites

Abstract: Within decades of development, carbon nanomaterials such as carbon black, fullerene, carbon nanotube, carbon nanofiber, graphene and their combined nanofillers have been tremendously applied in polymer material industries, generating a series of fascinating multifunctional composites in the fields from portable electronic devices, sports, entertainments to automobile, aerospace and military. Among the various material properties of the composites, electrical conductivity and mechanical performance are the two most important parameters for evaluating the effectiveness of nanofillers in the polymer matrices. In this review, we focus on the electrical and mechanical properties of diverse dimensional carbon nanofillers (e.g., zero-, one-, two-, three-dimensional nanofillers or their combinations)-reinforced polymer composites to seek the most efficient and effective approach to obtain high-performance polymeric nanocomposites.

Enhanced reduction of graphene oxide by high-pressure hydrothermal treatment

Abstract: A high-pressure assisted hydrothermal treatment is proposed as a facile, green and efficient route for the reduction of aqueous dispersions of graphene oxide. Reactions were performed in an autoclave at mild temperature (180 °C) using only water and nitrogen or hydrogen gas. No further separation or purification of the reduced products was required. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis revealed that the application of high pressure significantly enhanced oxygen removal. The C/O atomic ratio of the graphene oxide sheets increased from 1.65 to 5.29 upon conventional hydrothermal treatment using autogenous pressure. Higher C/O ratios of 6.35 and 7.93 were obtained for graphene oxides that were reduced under high-pressure of nitrogen and hydrogen, respectively. Specifically, the use of high-pressure hydrogen improved the removal of oxygen double-bonded to carbon. The introduction of covalently bonded heteroatoms, which is commonly observed for the use of reductants such as hydrazine, was not detected. Furthermore, high-pressure reduction led to a better restoration of the sp2 conjugation than was obtained by conventional hydrothermal treatment, as determined by XPS and Raman spectroscopies. These findings illustrate the promise of high-pressure hydrothermal treatments for the eco-friendly mass production of reduced graphene oxide.