MIT-World Peace University (MIT-WPU) is a top educational institute located in Pune, India. It is recognized within&nbsp;UGC under Government of Maharashtra Act No. XXXV 2017.&nbsp;

It is part of the MIT group of institutions (established in 1983) which covers 10+ campuses across India and has more than 50,000+ students enrolled across various disciplines at a given point of time. The institute houses 15 schools ranging from Engineering &amp; Technology, Design, Pharmacy, Commerce, Governance among others. It offers undergraduate, postgraduate and PhD programs among different disciplines.&nbsp;

&nbsp;

MIT World Peace University

School of Polymer Engineering

The tetrazole is an important functionality of the most of energetic materials due to 80% nitrogen content, stability, and high enthalpy of formation. The present structure-property relationship study focuses on the optimized geometries of tetrazole derivatives obtained from density functional theory (DFT) calculations at B3LYP/6-31G*levels. The heat of formation (HOF) of tetrazole derivatives have been calculated by designing the appropriate isodesmic reactions. The increase in nitro groups on azole rings shows the remarkable increase in HOF. Density has been predicted by using CVFF force field. Increase in the nitro group increases the density. Detonation properties of the designed compounds were evaluated by using the Kamlet-Jacobs equation based on predicted densities and HOFs. Designed tetrazole derivatives show detonation velocity (D) over 8 km/s and detonation pressure (P) of about 32 GPa. Thermal stability was evaluated via bond dissociation energies (BDE) of the weakest C-NO2 bond at B3LYP/6-31G*level. Charge on the nitro group has been used to assess the sensitivity correlation. Overall, the study implies that designed compounds of this series are found to be stable and expected to be the novel candidates of high energy materials (HEMs). © 2011 Springer Science+Business Media, LLC.

World University root node

Engineering and Technology

Structural Chemistry

Computational studies on tetrazole derivatives as potential high energy materials

Quantum chemical studies have gained paramount importance in screening of thermodynamically feasible chemical processes. The current investigation attempts to select an appropriate process for the synthesis of 1,3,5-triamino-2,4,6-trinitro benzene (TATB), a reasonably powerful insensitive high explosive (IHE) through density functional theory (DFT) calculations. Although, 1,3,5-trichlorobenzene (TCB) and 1,3,5-trihydroxybenzene (THB) routes for synthesis of TATB have been well established, this article demonstrates the predictive capability of thermochemical computations for the identification of a viable process. Thermochemical parameters of reaction species have been obtained from DFT B3LYP/6-31G* calculations and feasibility of the process has been worked out on the basis of free energies of reactions and equilibrium constant as derived from standard enthalpy and entropy of the reaction species. The detailed computational studies have revealed that the THB route is thermodynamically feasible and the same has been supported experimentally. © Taylor & Francis Group, LLC.

Journal of Energetic Materials

Quantum-chemical studies on TATB processes

The present article evaluates the effect of variation of WF on the tensile strength, modulus, and elongation at break. The pin-bearing properties usually correlate well with tensile properties. Tensile strength and pin-bearing strength decrease but tensile modulus increases on addition of WF. The tensile strength, pin-bearing strength, and mode of pin-bearing failure also depends on the void content. Increase in void content has a detrimental effect on all the mechanical properties. Wide variation is observed in impact strength because of unpredictable void content due to use of non-vented extrusion process. TGA indicates insignificant effect of WF on thermal stability of composites. Infrared spectroscopy indicates some interaction between PVC and WF. © The Author(s), 2010.

Fulltext

Journal of Reinforced Plastics and Composites

Mechanical properties of highly filled PVC/wood-flour composites

Polyethersulfone (PES)-expanded graphite nanocomposites have been prepared by solution blending route after sonicating expanded graphite in dichloromethane. It has been observed that ultrasonication results in nanosheets formation leading to a low percolation threshold of 3wt.%. At 5wt.% filler loading the conductivity is of the order of 10-2S/cm. Hopping type of charge transport occurs at 3.2wt.% expanded graphite in PES below which capacitive effects couple. The effective dielectric constant at low frequency increases with filler concentration. Impedance measurement has been carried out to evaluate interfacial capacitance which, for 3.2wt.% expanded graphite addition in PES, increases to 110pF from 32pF for 1wt.% expanded graphite in the polymer. DSC analysis shows an increment of 12°C in the Tg of PES with 3wt.% expanded graphite suggesting interaction between the polymer and filler. © 2010 Elsevier Ltd.

Composites Science and Technology

Polyethersulfone-expanded graphite nanocomposites: Charge transport and impedance characteristics

Viscoelastic and dielectric properties of composites with polyvinyl chloride as major matrix constituent, ethylene vinyl acetate (EVA) as polymeric plasticizer, and wood flour (WF) and fly ash (FA) as filler have been studied. The effect of variation of WF, FA, and EVA on storage modulus E', loss modulus E", and glass transition temperature, Tg has been evaluated using dynamic mechanical analysis (DMA). Effect on permittivity ε' and conductivity is evaluated using dielectric analysis. The results show considerable influence of constituents of the composite on the properties evaluated. DMA shows that WF contributes to an increase in Tg, E', and E" and a decrease in loss tangent, tan δ. The FA content has insignificant effect on these properties. Increasing WF content increases ε'. © 2009 Society of Plastics Engineers.

Polymer Engineering and Science

Characterization of highly filled wood flour-polyvinyl chloride composites: Dynamic mechanical and dielectric analysis

Hybrid composites with expanded graphite (ExGr) as the second conducting component in PPS-7 wt% graphite have been prepared by powder mixing method. The percolation threshold in the hybrid composites lies at 0.25wt% ExGr. Addition of 1 wt% ExGr in PPS-7 wt% graphite increases through plane conductivity by six orders compared to 0 wt% ExGr addition. The ac conductance study reveals that insulatorsemiconductor transition occurs at higher loading of ExGr in hybrid composites. For 0.75 wt%ExGr addition in PPS-7 wt% graphite, the charge transport occurs by hopping mechanism. Expanded graphite sheets predominantly occupy intergraphite spaces in hybrid composites. Impedance measurement has been carried out to evaluate interfacial capacitance which increases with enhanced ExGr loading. The composites are characterized by SEM, Impedance etc. © Central Institute of Plastics Engineering & Technology 2010.

International Journal of Plastics Technology

Polyphenylene sulfide-graphite hybrid composites: Charge transport and impedance characteristics

Polypyrrole (PPy) was chemically functionalized with 5,10,15,20-tetraphenyl-21H,23H-porphyrin iron(III) chloride (FeTPPCl) with special interest on noxious carbon monoxide (CO) gas in ppm level. Controlled functionalization of PPy was achieved with incorporation of various concentrations of porphyrin. The resulted semiconducting material was well characterized by different techniques such as UV-vis spectroscopy, FTIR, GFAAS, XRD, and EDAX. The functionalized polypyrrole material on interdigitated electrode was experienced an immediate increase in resistance when exposed to carbon monoxide gas at very low concentration. The CO gas interacted very fast with the FeTPPCl functionalized PPy at room temperature (RT) and then slowly saturated. The response of these materials was not unidirectional, but reverses to the original resistance level when CO was removed from the test chamber. The highest response factor (ΔR/R0 × 100) and lowest response time (t50) obtained are 12 and 169 s, respectively. An optimum level of doping (1 mol% of FeTPPCl) was established for the highest sensitivity and the detection level is as low as 100 ppm. © 2009 Elsevier B.V. All rights reserved.

Synthetic Metals

CO sensor based on polypyrrole functionalized with iron porphyrin

Incorporation of polyaniline (PANI) in epoxy type powder coating formulations has not been attempted earlier. Using specific grade of PANI with low doping, it can be incorporated in epoxy powder coating formulations by twin screw extrusion process. The powder formulations were deposited on steel substrates by electrostatic spray coating at -60 kV and baked at 140 °C for 20 min. These were extensively tested for corrosion resistance by exposure to hot saline conditions followed by electrochemical impedance spectroscopy and also salt spray testing. PANI incorporated coatings showed no deterioration even after 1400 h of hot (65 °C) saline treatment. The coatings intentionally scratched also exhibited self healing property and there was no rust formation even after prolonged exposure to hot saline conditions. These results could be explained on the basis of additional crosslinking due to PANI, as confirmed by DSC results, which gave rise to improved barrier property and self healing was associated with the scavenging of ions by PANI which prevented corrosion of the underlying substrate. © 2008 Elsevier B.V. All rights reserved.

Progress in Organic Coatings

Epoxy powder coatings containing polyaniline for enhanced corrosion protection

In this study, we report an approach for the adsorption and desorption of anionic (sulfonated) dyes from aqueous solution by doped polyaniline. In this study, we have synthesized PANI with two dopants, namely, p-toluenesulfonic acid (PTSA) and camphorsulfonic acid (CSA), and used these to adsorb various dyes. It was found that the doped PANI selectively adsorbs anionic dyes and does not adsorb cationic dyes. The adsorption of anionic dyes causes the variation in electrical conductivity of PANI, indicating its potential as a conductometric sensor for these dyes at very low concentration. The adsorbed dyes were desorbed from the polymer by using a basic aqueous solution. The adsorption and desorption kinetics of the dye in the presence of doped PANI were also determined. © 2009 American Chemical Society.

Journal of Physical Chemistry B

Adsorption and Desorption Kinetics of Anionic Dyes on Doped Polyaniline

Thiophene monomer structures containing different hetero aromatic rings (containing five-member/six-member, varying electronegativity, functional groups) were designed and synthesized. The influence of structural components of the side chain on the thermal stability of the polymers of the above monomers was analyzed using thermogravimetric analysis. The results show that thiophene-containing hetero aromatic side chains linked through six-member ring show high thermal stability. © 2009 Springer Science+Business Media, LLC.