Thermally induced microstructural changes and its influence on electrical conductivity of a polymer-based bakelite RPC detector material: A positron lifetime study

Veedu, A. K. K. and Basavaraju, R. H. and Chikkakuntappa, R. (2013) Thermally induced microstructural changes and its influence on electrical conductivity of a polymer-based bakelite RPC detector material: A positron lifetime study. Journal of Applied Polymer Science, 130 (2). pp. 793-800.

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Official URL: http://doi.org/10.1002/app.39234

Abstract

Annealing studies have been carried out to understand the temperature induced microstructural changes in Bakelite (P-120 NEMA LI-1989 Grade XXX) Resistive Plate Chamber (RPC) detector material using Positron annihilation lifetime spectroscopy (PALS), Fourier transform infrared spectroscopy (FTIR), and XRD. The variation of positron lifetime parameters viz., ortho-Positronium lifetime (�3) and free volume size (Vf) increases marginally above glass transition temperature Tg as a result of structural changes due to segmental mobility. The drastic increase of free volume parameters above 240°C attributed to the reduction in strength of C - H bond of the aliphatic bridges and cleavage of methylene bridges of the polymer network, which is supported by the FTIR results. The XRD results show the reduction in crystallinity and average crystallite size of Bakelite on annealing correlates well with the free volume and electrical conductivity. The temperature induced electrical conductivity and activation energy is also correlated with the positron lifetime parameters.

Item Type: Article
Uncontrolled Keywords: Activation energy, Degradation, Differential scanning calorimetry, Elastomers, Electric conductivity, Electrical conductivity, Fourier transform infrared spectroscopy, Free volume, Microstructural changes, ortho-Positronium lifetime, Particle spectrometers, Positron annihilation lifetime spectroscopy, Positron annihilation spectroscopy, Positron lifetime study, Positrons, Resistive plate chambers, Segmental mobility, Temperature-induced
Subjects: D Physical Science > Physics
Divisions: Department of > Physics
Depositing User: Arshiya Kousar Library Assistant
Date Deposited: 10 Dec 2019 06:28
Last Modified: 10 Dec 2019 06:28
URI: http://eprints.uni-mysore.ac.in/id/eprint/9543

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