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| Volume 6, Issue 01 - 2010 |
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| 4 |
ACTIVATION ENERGY OF á- AND â- RELAXATION PROCESS OF PMMA AND CdS-PMMA NANOCOMPOSITE |
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| Pages 28-34 |
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| MANASVI DIXIT*, VISHAL MATHUR, SANDHYA GUPTA, KANANBALA SHARMA AND N.S. SAXENA |
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| Semiconductor and Polymer Science Laboratory, Department of Physics, University of Rajasthan, Jaipur 302 004 India |
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| Received 17 August 2009; accepted 16 December 2009 |
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| The present study investigates the effect of dispersed CdS on the á- and â-relaxation processes of PMMA. DMA has been employed at different frequencies in the range from 0.316-31.6 Hz at temperatures from –80 °C to 150 °C to study the dynamics of films of thickness ~ 0.05 mm of PMMA and CdS-PMMA composite. PMMA polymer exhibits two relaxation processes: primary (glass, or) á-relaxation and â-relaxation process. The former is associated with the glass-rubber transition and is characterized by Vogel-Fulcher-Tammann temperature dependence and the latter is related to the local motion of the ester side groups attached to the polymer backbone. As the frequency increases, the transition peaks of PMMA shift towards higher temperature and a decrease in the strength of relaxation is observed. CdS-PMMA composite also shows á and â relaxation processes and are observed at higher values of temperature as compared to pure PMMA. The activation energy of á-relaxation has been determined from VFT equation and for â- relaxation the activation energy has been determined by Arrhenius plot.
Keywords: Dynamic Mechanical Analyser, á and â relaxations, glass transition temperature, Arrhenius plot, activation energy |
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