Abstract
Isothermal annealing of poly(chlorotrifluoroethylene) (PCTFE) was carried out at a temperature of 70 °C (slightly above T g ) using the positron annihilation lifetime (PAL) technique. Both the o-Ps lifetime and intensity shows systematic variation with ageing time, and its intensity can be represented by two additive decay exponentials. The free volume which is estimated using the Nakanishi et al. equation developed from Tao's model, exhibits Doolittle type free volume relaxation. Physical ageing seems to yield close packing of polymer chains without crystallization. The relaxation time, and the nonexponentiality parameter, were estimated using a Kolrausch-Williams-Watt (KWW) function.
Published Version
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