Influence des traitements thermiques à l'état fondu sur les cinétiques de cristallisation du poly(oxyméthylène) |
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Authors: | Alain Franbourg,Fran ois Rietsch |
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Affiliation: | Alain Franbourg,François Rietsch |
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Abstract: | The influence of the temperature of the melt T1 on the kinetics and the morphology of a semicrystalline polymer (poly(oxymethylene)) was investigated using thermal analysis and optical microscopy. The thermodynamic melting point T and the enthalpy of melting at thermodynamical equilibrium ΔH were determined by extrapolation of the graphs Tf = f(Tc) and ΔHf = f(Tc); (T = 198°C, ΔH = 251 J/g). For different temperatures of the melt (T1 = 185°C, 195°C, 205°C), isothermal and non-isothermal crystallizations were analysed using the Avrami and Ozawa equations. Nucleation and spherulitic growth in this polymer were studied by using optical microscopy at elevated temperatures. Using different analyses, we observed initial nucleation followed by spherulite growth with the following influence of the temperature of the melt on the distribution and the number of spherulites: T1 < T produces many small spherulites; T1 > T gives rise to few large spherulites. |
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