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16 results on '"Bajpai, O. P."'

7. A Brief Overview on Ferrite (Fe3O4) Based Polymeric Nanocomposites: Recent Developments and Challenges

Author

Bajpai, O. P., Setua, D. K., Chattopadhyay, S., Bajpai, O. P., Setua, D. K., and Chattopadhyay, S.

Abstract

In this article, we have mainly discussed about ferrite (Fe3O4) and its polymer based nanocomposites. Ferrite particles have become an important research material because of their vast applications in the field of biotechnology, magnetic resonance imaging (MRI), and data storage. It has been observed that ferrite Fe3O4 particles show best performance for size less than 10-30 nm. This happens due to the super paramagnetic nature of such particles. In super paramagnetic range these particles exhibit zero remanence or coercivity. Therefore, various properties of ferrite (Fe3O4) nanoparticles and its polymer nanocomposites are very much dependent on the size, and distribution of the particles in the polymeric matrix. Moreover, it has been also observed that the shape of the nanocrystals plays important role in the determination of their fundamental properties. These particles show instability over longer times due to the formation of agglomerates generated by high surface energies. Therefore, protection strategies such as grafting and coatings with silica/carbon or polymers have been developed to stabilize them chemically. Recently, silylation technique is mainly used for the modification of nanoparticles. Experimentally, it has been observed that nanocomposites composed of polymer matrices and ferrite showed substantial improvements in stiffness, fracture toughness, sensing ability (magnetic as well as electric), impact energy absorption, and electro-catalytic activities to bio-species.

Published
2015

12. Effect of surface modification of BiFeO3 on the dielectric, ferroelectric, magneto-dielectric properties of polyvinylacetate/BiFeO3 nanocomposites.

Author

Bajpai, O. P., Kamdi, J. B., Selvakumar, M., Ram, S., Khastgir, D., and Chattopadhyay, S.

Subjects
*DIELECTRIC properties, *FERROELECTRICITY, *POLYVINYL acetate, *CALOTROPIS, *ETHYL silicate, *WETTING
Abstract

Bismuth ferrite (BiFeO3) is considered as one of the most promising materials in the field of multiferroics. In this work, a simple green route as well as synthetic routes has been used for the preparation of pure phase BiFeO3. An extract of Calotropis Gigantea flower was used as a reaction medium in green route. In each case so formed BiFeO3 particles are of comparable quality. These particles are in the range of 50-60 nm and exhibit mixed morphology (viz., spherical and cubic) as confirmed by TEM analysis. These pure phase BiFeO3 nanoparticles were first time surface modified effectively by mean of two silylating agent's viz., tetraethyl orthosilicate (TEOS) and (3-Aminopropyl)triethoxysilane (APTES). Modified and unmodified BiFeO3 nanoparticles were efficiently introduced into polyvinylacetate (PVAc) matrix. It has been shown that nanocomposite prepared by modified BiFeO3 comprise superior dispersion characteristics, improved ferroelectric properties and favorable magneto-dielectric properties along with excellent wettability in compare to nanocomposite prepared by unmodified BiFeO3. These preliminary results demonstrate possible applications of this type of nanocomposites particularly in the field of multiferroic coating and adhesives. [ABSTRACT FROM AUTHOR]

Published
2014
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16. A study of splenoportovenography in infantile cirrhosis of liver.

Author

Bajpai OP, Dwivedi MS, Singh SD, Chhaparwal BC, and Pohowalla JN

Subjects
Child, Preschool, Collateral Circulation, Female, Humans, Infant, Liver Cirrhosis diagnosis, Liver Function Tests, Male, Portography, Liver Cirrhosis diagnostic imaging
Published
1972

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