Influence of annealing and chain defects on the melting behaviour of poly(vinylidene fluoride) |
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Authors: | C Marega |
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Institution: | Dipartimento di Chimica Inorganica, Metallorganica ed Analitica dell’Università, via Loredan 4, 35131 Padova, Italy |
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Abstract: | The melting behaviour of poly(vinylidene fluoride) (PVDF) was investigated by differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering in order to study the influence of the chain defects content and of the temperature of annealing on the crystallization and melting behaviour.All the DSC scans show a double endotherm and the analysis of the data suggests that the low temperature endotherm is due to the melting of a population of thin lamellae, whose thickness increases during the annealing, but a high content of chain defects prevents the lamellar thickening and the main effect in this case is the crystallization of thin lamellae from a portion of polymer which did not crystallize during the quenching from the melt. Furthermore, the two melting endotherms, which are observed, can be partially ascribed to a melting-recrystallization process.Furthermore, stepwise isothermal cooling was performed in a differential scanning calorimeter followed by melting scans of fractionated PVDF samples to point out the possible presence of a series of endothermic peaks. |
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Keywords: | Poly(vinylidene fluoride) Melting behaviour Annealing Chain defects X-ray scattering Differential scanning calorimetry |
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