Six samples of isotactic polypropylene were examined to study the influence of the thermal treatments and the molecular weights and their distribution on the β-crystallization of the polymer. The highest amount of the β-phase was obtained by isothermal crystallization and in correspondence of high average molecular weights and wide molecular weight distributions. Small-angle X-ray scattering pointed out that a partial β-crystallization seems not to influence the lamellar morphology parameters. Differential scanning calorimetry measurements, at different heating rates, allowed us to confirm that the multiple melting endotherms behavior of the β-phase is to be correlated to a melting–recrystallization–melting mechanism.

Influence of thermal treatments, molecular weight, and molecular weight distribution on the crystallization of beta-isotactic polypropylene

MARIGO, ANTONIO;MAREGA, CARLA;CAUSIN, VALERIO;
2004

Abstract

Six samples of isotactic polypropylene were examined to study the influence of the thermal treatments and the molecular weights and their distribution on the β-crystallization of the polymer. The highest amount of the β-phase was obtained by isothermal crystallization and in correspondence of high average molecular weights and wide molecular weight distributions. Small-angle X-ray scattering pointed out that a partial β-crystallization seems not to influence the lamellar morphology parameters. Differential scanning calorimetry measurements, at different heating rates, allowed us to confirm that the multiple melting endotherms behavior of the β-phase is to be correlated to a melting–recrystallization–melting mechanism.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2459615
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