scispace - formally typeset
Search or ask a question
Author

Dipak Khastgir

Bio: Dipak Khastgir is an academic researcher from Indian Institute of Technology Kharagpur. The author has contributed to research in topics: Polyaniline & Carbon black. The author has an hindex of 48, co-authored 201 publications receiving 8434 citations. Previous affiliations of Dipak Khastgir include Federal University of Rio de Janeiro & Indian Institutes of Technology.


Papers
More filters
Journal ArticleDOI
TL;DR: A detailed discussion on the mechanism of electrical conduction in PANI and the factors those influence the conductivity of PANI is also included in this paper, where the problems of effective utilization and the methods adopted to overcome these problems are also provided.

1,632 citations

Journal ArticleDOI
TL;DR: In this paper, the authors studied the EMI shielding characteristics of natural rubber and ethylene vinyl acetate filled with conductive carbon black (Vulcan XC-72) and short carbon fibre (SCF) in two different frequency ranges 100-2000 MHz and 8-12 GHz (X-band range).
Abstract: Electromagnetic interference (EMI) shielding characteristics of natural rubber and ethylene vinyl acetate filled with conductive carbon black (Vulcan XC-72) and short carbon fibre (SCF) have been studied. The measurements of shielding effectiveness (SE) were carried out in two different frequency ranges 100–2000 MHz and 8–12 GHz (X-band range). The return loss and loss due to absorption were also measured as a function of frequency in the X-band range and microwave region. It is observed that the SE of the composites is frequency dependent, especially at higher frequency range, and it increases with the increasing frequency. The SE also increases with the increase in filler loading. The SCF filled composites show higher SE compared to that of conductive carbon black. The correlation between SE and conductivity of the various composites is also discussed. The results indicate that the composites having higher fibre loading (≥20 phr) can be used for the purpose of EMI shielding, as well as for some microwave applications.

370 citations

Journal ArticleDOI
TL;DR: In this paper, the authors report the mechanical, morphological, water absorption, thermal conductivity, and thermal behavior of rigid polyurethane foam varying with the density, which controls the foam architecture.
Abstract: Density is an important parameter that influences the properties and performances of rigid polyurethane foam (PUF). Rigid PUF with different densities were prepared by varying the amount of distilled water as blowing agent. This investigation reports the mechanical, morphological, water absorption, thermal conductivity, and thermal behavior of rigid PUF varying with the density, which controls the foam architecture. The density of the PUF decreased from 116 to 42 kg/m3 with an increase in the amount of water from 0.1 to 3.0 parts per hundred polyol by weight (phr), respectively. It was found that the mechanical properties of the PUFs changed with the foam density. The results of water absorption of the PUFs showed that water absorption increased with decrease in density, due to increase in the cell size and decrease in the cell-wall thickness. The thermal conductivity measurements showed that the thermal conductivity decreased with increase in density. It was due to the decrease in cell size. The thermal analysis of the PUFs shows that the glass transition temperature increases with the decrease in foam density, but the thermal stability decreases with the decrease in foam density. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

266 citations

Journal ArticleDOI
TL;DR: In this paper, water-blown rigid polyurethane foam (PUF) was prepared with melamine polyphosphate (MPP) and melamine cyanurate (MC) as fire retardant (FR) additives.

184 citations

Journal ArticleDOI
TL;DR: In this article, the effect of different techniques on the electric properties (dielectric constant, dielectric losses, and complex electric modulus) of the corresponding emeraldine base has been studied.

172 citations


Cited by
More filters
Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: In this paper, the structure, preparation and properties of polymer/graphene nanocomposites are discussed in general along with detailed examples drawn from the scientific literature, and the percolation threshold can be achieved at a very lower filler loading.

2,999 citations

Journal ArticleDOI
TL;DR: Graphene has emerged as a subject of enormous scientific interest due to its exceptional electron transport, mechanical properties, and high surface area, and when incorporated appropriately, these atomically thin carbon sheets can significantly improve physical properties of host polymers at extremely small loading.
Abstract: Graphene has emerged as a subject of enormous scientific interest due to its exceptional electron transport, mechanical properties, and high surface area. When incorporated appropriately, these atomically thin carbon sheets can significantly improve physical properties of host polymers at extremely small loading. We first review production routes to exfoliated graphite with an emphasis on top-down strategies starting from graphite oxide, including advantages and disadvantages of each method. Then solvent- and melt-based strategies to disperse chemically or thermally reduced graphene oxide in polymers are discussed. Analytical techniques for characterizing particle dimensions, surface characteristics, and dispersion in matrix polymers are also introduced. We summarize electrical, thermal, mechanical, and gas barrier properties of the graphene/polymer nanocomposites. We conclude this review listing current challenges associated with processing and scalability of graphene composites and future perspectives f...

2,979 citations

Journal ArticleDOI
Qiong Wu1, Yuxi Xu1, Zhiyi Yao1, Anran Liu1, Gaoquan Shi1 
31 Mar 2010-ACS Nano
TL;DR: Supercapacitor devices based on this conductive flexible composite film showed large electrochemical capacitance at a discharge rate of 0.3 A g(-1) and exhibited greatly improved electrochemical stability and rate performances.
Abstract: Composite films of chemically converted graphene (CCG) and polyaniline nanofibers (PANI-NFs) were prepared by vacuum filtration the mixed dispersions of both components. The composite film has a layered structure, and PANI-NFs are sandwiched between CCG layers. Furthermore, it is mechanically stable and has a high flexibility; thus, it can be bent into large angles or be shaped into various desired structures. The conductivity of the composite film containing 44% CCG (5.5 × 102 S m−1) is about 10 times that of a PANI-NF film. Supercapacitor devices based on this conductive flexible composite film showed large electrochemical capacitance (210 F g−1) at a discharge rate of 0.3 A g−1. They also exhibited greatly improved electrochemical stability and rate performances.

2,089 citations

Journal ArticleDOI
01 Feb 2001-Carbon
TL;DR: Carbon materials for electromagnetic interference (EMI) shielding are reviewed in this article, including composite materials, colloidal graphite and flexible graphite, and they include carbon filaments of submicron diameter.

1,676 citations