Influence of vinylidenefluoride on the physical ageing of poly(chlorotrifluoroethylene) |
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Authors: | C Ranganathaiah R RamaniP Ramachandra |
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Institution: | a Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006, India b Department of Pathology, Armed Forces Medical College, Pune 411 040, India c KGF First Grade College, KGF, Karnataka, India |
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Abstract: | The influence of vinylidenefluoride (3% composition) on the physical ageing of poly(chlorotrifluoroethylene) at 70 °C has been investigated using the positron annihilation lifetime technique. Both the ortho-positronium (o-Ps) pick-off lifetime and its intensity show a systematic variation with ageing time. The o-Ps intensity exhibits non-exponential character which can be fitted with two additive exponential decay curves and the free volume is found to exhibit the Doolittle type of free volume relaxation. The relaxation times were evaluated from the structural relaxation function and the non-exponentiality parameter was estimated using the Kohlrausch-Williams-Watts (KWW) function, which indicates the deviation from exponential relaxation. Based on the relaxation times, the activation energies calculated seems to label the different kinetic units/irregularity in the chain backbone of PCTFE structure participating in the relaxation process. Physical ageing seems to yield close packing of polymer chains. |
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Keywords: | Physical ageing Positron lifetime Poly(chlorotrifluoroethylene) Structural relaxation |
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