Dr. Kallol Das

@staloysiuscollege.ac.in

Vice Principal
St. Aloysius College (Autonomous), Jabalpur. Madhya Pradesh. India

Dr. Kallol Das


            Download Compact PDF  
https://researchid.co/kalloldas

RESEARCH, TEACHING, or OTHER INTERESTS

Condensed Matter Physics, Polymers and Plastics, Materials Science, Modeling and Simulation
16

Scopus Publications

Scopus Publications

  • A study of the optical band gap energy and urbach energy of fullerene (C60) doped PMMA nanocomposites
    A. Dhanaraj, K. Das, J. M. Keller
    Aip Conference Proceedings, 2020
    Fullerene dispersion in a polymer matrix alters the values of band gap energy and Urbach energy of the nanocomposite. In the presented work, the influence of fullerene dispersion and polymer-fullerene interactions on the band gap energy and Urbach energy of poly (methyl methacrylate)-fullerene C60 nanocomposite has been studied by means of UV-Vis absorption spectroscopy. Pure and different doped films of gradually increasing concentrations were fabricated using solvent casting technique. Optical properties of these films were obtained from the UV-VIS absorption spectra, at normal incidence, over190-1100 nm spectral range. The optical absorption edge was described using the Tauc model. Band gap energy of the thin films was found using Tauc plot. The width of the band tails, known as Urbach tails, were evaluated to quantify the structural disorder. Optical characterization showed that average absorption and band gap energy decreased, while Urbach energy increased with the addition of fullerene C60.
  • Variation of micro-hardness of titanium oxide doped poly (methyl methacrylate) composite samples with different annealing temperature
    P. Pendke, K. Das, J. M. Keller
    Aip Conference Proceedings, 2019
    The variation of micro-hardness of titanium oxide doped poly (methyl methacrylate)compositesamples with different annealing temperature is reported in the present work.Poly (methyl methacrylate) samples have been used as the host material in which titanium oxide is added in different weight % of doping (0%,0.0001%, 0.0005%, 0.005%, 0.001%, 0.05%, 0.01%). The sample preparation was done by solution casting method. For the present studies Vicker’s microhardness test has been used. The sample is subjected to loads of 10-200 grams. INTRODUCTION Hardness measures material resistance to indentation. The term ‘hardness’ can have various meanings in different contexts, for example implying resistance to elastic deformation in the case of elastomeric materials or resistance to groove formation in scratching[1].Hardness is known as “Resistance of solid material to plastic deformation”, usually by indentation. However, the term may also refer to stiffness or temper or to resistance to scratching, abrasion, or cutting. It is the property of a solid, which gives it the ability to resist being permanently, deformed (bent, broken, or have its shape changed), when a load is applied. The greater the hardness of the solid, the greater it has resistance to deformation. Hardness measurement does not depend on a single physical property, but it involves both the elastic and plastic deformation characteristics of materials. PMMA is frequently preferred because of its moderate properties, easy handling and processing, and low cost. The micro hardness technique was used for many years for characterization of such “classical materials” as metals, alloys and inorganic glasses. Its application to polymeric materials developed during the last several decades [2].For the present studies Vicker’s micro hardness test has been used. This test uses a square pyramid of diamond in which the included angles a between non-adjacent faces of the pyramid are 136°. The hardness is given by = 1.854 where Pis the force in Kg and d is the mean diagonal length of the impression in millimeters. The value of HV is expressed in Kg/mm. The force is usually applied at a controlled rate, held for 30 s, and then removed [3-6]. MATERIALS Polymethyl methacrylate (PMMA) PMMA selected for the present work is one of the most important polymeric materials with good physical properties.PMMA, an ethylene derivative, is a synthetic polymer made by the chain growth method of polymerization [7]. PMMA is a transparent [8], high-strength commercially available amorphous thermoplastic polymer. PMMA exhibits prominent mechanical, dimensional, and thermal stabilities, as well as a high optical transparency with a relatively low glass transition temperature [9]. Titanium oxide Titanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula TiO2. Itis a fine white powder pigment, has a good light scattering ability, and therefore a good whiteness, high color strength, hiding power, strong at the same time have a high chemical stability and good weather ability. Preparation of pure PMMA and their polymer composite film samples Polymer composites were prepared by doping different concentrations i.e. 0.0001%, 0.0005%, 0.001%, 0.005%, 0.01% & 0.05% wt% of titanium oxide in PMMA with the help of solution casting method. PROCEDURE The PMMA samples have been used as the host material in which titanium oxide is added in different wt% doping (0.0001%,0.0005%,0.005%,0.001%,0.05%,and .01%). In The present work "Vaiseshika" Micro Hardness Tester (Type: 7005) has been used. The hardness number is defined as the ratio of the load applied to the indenter (gram or kilogram force) divided by the contact area of the impression (square millimeters). The Vickers hardness test method consists of indenting the test material with a diamond indenter. The indenter is in the form of a right pyramid with a square base and an angle of 136 degrees between opposite faces. The sample is subjected to loads of 100-200 gms. The two diagonals of the indentation left on the surface of the material after removal of the load are measured using a microscope and their average is calculated. The area of the sloping surface of the indentation is calculated.. In the present investigation the samples were fixed on an optically plane glass in such a way that the surface to be indented was always perfectly horizontal. The plate with the sample is mounted on the stage of the microscope to avoid displacement of the sample. The indenter was kept in contact with the surface for 30 seconds. The length of diagonal of the square was measured through a microscope. A number of measurements were carried out and average of the hardness values was taken. RESULTS AND DISCUSSION Annealing effects on the microstructure and morphology of polymer materials have been a subject of major technological and scientific interest for a number of years. Annealing has been performed to polymers for improving their crystalline order. There are many studies about annealing influences on the crystallization behavior of neat polymers [10].Annealing processes is time and temperature dependent [11].The effect of annealing temperature on pure PMMA and PMMA doped with titanium oxide has been investigated by annealing samples at temperatures 40°C, 60°C, 80°C,100°C and 115°C for 2 hours. Hv is plotted against annealing temperature for each load for pure as well as doped PMMA samples. The effect of annealing temperature on hardness of pure and composite samples has been shown by figures 17. Fig8 shows the variation of microhardness with temperature of pure PMMA for an applied load of 10 gm with error bars. 350 355 360 365 370 375 380 385 390 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8
  • Crystalline and absorption studies on PMMA/CdS composite using XRD & UV-Vis techniques
    Arunendra Kumar Patel, Nidhi Jain, Pooja Patel, Kallol Das, Rakesh Bajpai
    Aip Conference Proceedings, 2018
    The composite of PMMA and CdS powder were prepared by solution casting technique after sonication for 60 min. The Crystallinity Index, Interplanar Distance, Crystallite Size, Average Inter Crystalline Separation and Energy Band Gap have been estimated for the prepared samples. The crystallinity index is increasing from 39.74% for pure PMMA to 41.45% for 1%CdS+PMMA composite film. The crystallite size is decreasing with increasing the concentration of CdS. The energy band gap of Pure PMMA from absorption spectra was found to be 4.542eV, which decreases with concentration of CdS powder within PMMA matrix.
  • Concentration dependent optical properties of rhodamine B doped poly(vinyl alcohol) solutions
    Jitendra Tripathi, Anupam Sharma, Shilpa Tripathi, Kallol Kumar Das
    Macromolecular Research, 2016
  • Nano-engineered optical properties of iodine doped poly(methyl methacrylate)
    Sheetal Mehta, Jag Mohan Keller, Kallol Das
    Aip Conference Proceedings, 2016
    Poly (methyl methacrylate) (PMMA) and Iodine hybrid matrixes have been prepared and characterized. The optical properties of the prepared I-PMMA hybrid composites were characterized by linear absorption studies and these composites have been found to contain embedded Iodine nanoparticles. The size of the nanoparticles was found to be a function of the Iodine content of PMMA. Refractive index measurements were undertaken for different wavelengths. The results showed that the refractive index of the composite is dependent on thermal annealing and also varies nonlinearly with the doping concentration at low Iodine concentration or in the region of nanoparticles formation.
  • Abbe's number and Cauchy's constant of iodine and selenium doped poly (methylmethacrylate) and polystyrene composites
    Sheetal Mehta, Kallol Das, Jag Mohan Keller
    Aip Conference Proceedings, 2014
    Poly (methyl methacrylate) / Polystyrene and iodine / selenium hybrid matrixes have been prepared and characterized. Refractive index measurements were done at 390, 535, 590, 635 nm wavelengths. Abbe's number and Cauchy's constants of the iodine / selenium doped poly (methylmethacrylate) and polystyrene samples are being reported. The results also showed that the refractive index of the composite varies non-monotonically with the doping concentration at low iodine concentration or in the region of nanoparticles formation and is also dependent on thermal annealing.
  • Correlation between microhardness and surface properties of Rhodamine B doped PVA films
    J. Tripathi, S. Tripathi, A. Sharma, T. Shripathi, J. M. Keller, K. Das
    Aip Conference Proceedings, 2014
    The degradation in microhardness of Rhodamine B doped PVA films is discussed as a function of doping. It is shown how the bigger size (∼ 45-60 nm) dopant crystallites change the hardness of host PVA containing smaller (∼4 nm) crystallites. At higher doping, dye molecules segregate to the surface breaking the bonds of the PVA matrix and hence reducing the microhardness. The results are supported by XPS, which reveals breaking of the bonds. Overall results are interpreted in terms of bond modifications in PVA due to inclusion of Rhodamine B molecules.
  • Annealing induced variation in refractive index of Rhodamine B doped Poly (vinyl) alcohol films
    J. Tripathi, S. Tripathi, J.M. Keller, K. Das
    Journal of Physics and Chemistry of Solids, 2013
  • Surface properties of rhodamine B doped poly (vinyl) alcohol films studied using XPS and AFM
    J. Tripathi, S. Tripathi, J. M. Keller, K. Das, T. Shripathi
    Aip Conference Proceedings, 2013
    We present the observations on bonding and surface morphology of 2 wt% Rhodamine B doped poly (vinyl) alcohol film. Surface sensitive XPS measurements show high quality impurity free films, where the bonding is found between C and O elements is observed. These results are further supported by AFM, which beautifully reveal the segregation of foreign molecules (Rhodamine B) so that the condition of minimum energy is reached which is necessary in order to make the polymer system stable.
  • Degradation study on structural and optical properties of annealed Rhodamine B doped poly(vinyl) alcohol films
    J. Tripathi, S. Tripathi, J.M. Keller, K. Das, T. Shripathi
    Polymer Degradation and Stability, 2013
  • Structural, optical and chemical characterization of Rhodamine (B) doped poly (vinyl) alcohol films
    J. Tripathi, J.M. Keller, K. Das, S. Tripathi, A. Fatima, T. Shripathi
    Applied Surface Science, 2012
  • Influence of Rhodamine (B) doping on vibrational, morphological and absorption properties of poly(vinyl) alcohol
    J. Tripathi, J.M. Keller, K. Das, S. Tripathi, T. Shripathi
    Journal of Physics and Chemistry of Solids, 2012
  • Charge transport parameter of iodine-PMMA composites
    R. D'souza, J.M. Keller, K. Das
    Proceedings International Symposium on Electrets, 2011
  • Optical properties of iodine-PMMA composites
    R. D'souza, J.M. Keller, K. Das
    Proceedings International Symposium on Electrets, 2011
  • On the suitability of dispersion models for the optical dispersion of poly(ethyl methacrylate)
    Kallol Das, Sheetal Mehta, Shruti Patankar, Alka B. Garg, R. Mittal, R. Mukhopadhyay
    Aip Conference Proceedings, 2011
  • Blue shifts and refractive index of rhodamine 6G doped polycarbonate
    Kallol Das, Sheetal Mehta, Rashmi Singh, Alka B. Garg, R. Mittal, R. Mukhopadhyay
    Aip Conference Proceedings, 2011

GRANT DETAILS

Optical Profiling of TiO2 doped PMMA Films: A Study of the Refractive Index, Optical Transition, Optical Band Gap and Urbach Energy Parameters
Funding Agency : UGC
Completed Investigator 500000 2014 - 2016

Electronic and Transport Properties of Iodine Doped Polymethylmethacrylate Films
Funding Agency : UGC
Completed Investigator 45000 2004 - 2006