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Swift heavy ion-induced modification of the physical properties of polymethyl methacrylate/carbon black composites

Singh, N. L. and Singh, Dolly and Qureshi, Anjum (2011) Swift heavy ion-induced modification of the physical properties of polymethyl methacrylate/carbon black composites. Radiation Effects and Defects in Solids (Special Issue), 166 (8-9). pp. 640-647. ISSN 1042-0150

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Official URL: http://dx.doi.org/10.1080/10420150.2011.583245

Abstract

A carbon black (CB) filler was inserted into polymethyl methacrylate (PMMA) using a chemical route method. The electrical conductivity and dielectric properties of PMMA/CB composites were investigated in a wide range of frequencies: from 100 Hz to 10 MHz. These films were irradiated with 140 MeV Ag(11+) ions at a fluence of 1 x 10(12) ions/cm(2). The radiation-induced modifications in the dielectric, structural and thermal properties and in the surface morphology were studied using different techniques. The dielectric dispersion and conductivity of the composite system exhibited a strong frequency dependence, particularly in the vicinity of the percolation threshold (20 wt%). It was observed that the dielectric constant, dielectric loss and electrical conductivity gradually increased with the filler concentration and also with ion fluence; these were explained in terms of the hopping conduction mechanism. The electrical conductivity of the composites obeys the universal power law (i.e. sigma = Af(n)), where n is the power exponent. The results also suggest that ion beam irradiation of polymer composites creates free radicals and unsaturation and causes interfacial polarization in the heterogeneous composite systems. Thermal analysis revealed that the glass transition temperature (T(g)) shifted toward lower temperatures upon irradiation, indicating the scissioning of polymer chains which led to the transformation of the polymers into a disordered amorphous state. The changes in the topography of the surfaces upon irradiation were also observed.

Item Type:Article
Additional Information:Conference: International Conference on Swift Heavy Ions in Materials Engineering and Characterization (SHIMEC 2010) / Location: Inter Univ Accelerator Ctr (IUAC), New Delhi, INDIA / Date: OCT 06-09, 2010
Uncontrolled Keywords:dielectric properties; differential scanning calorimetry (DSC); radiation damage; polymethyl methacrylate (PMMA); carbon black (CB)
Subjects:T Technology > TK Electrical engineering. Electronics Nuclear engineering
Q Science > QC Physics > QC1 General
ID Code:16662
Deposited By:Anjum Qureshi
Deposited On:09 Aug 2011 16:37
Last Modified:10 Aug 2011 16:37

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