For the first time the kinetics of formation of syndiotactic polypropylene mesophase close to 0 8C through differential scanning calorimetry has been investigated. The calorimetric data have been analyzed through the well-known Avrami analysis. We have obtained Avrami coefficients less or at most equal to 2, which are likely to indicate a nearly bidimensionality of the crystallites. The morphology of the mesophase, not known up to now, has been examined through atomic forcemicroscopy (AFM): lamellar structures have been observed. The fractal dimension of the AFM images has been evaluated through the box counting method. It resulted about 2, in a very good agreement with the calculated Avrami coefficients. An infrared and diffractometer analysis on samples kept for increasing times at 0 8C has also been performed to confirm the calorimetric data. The experimental results allow one to better clarify the kinetics of mesophase-formation. It has been found that a time of 3 h at 0 8C is actually necessary for the complete crystallization of the trans-planar mesophase, a longer time is needed to stabilize the mesophase domains when the sample is extracted from 0 8C at room temperature

Crystallization Kinetics and Morphology of the Mesomorphic Form of Syndiotactic Polypropylene

PUCCIARIELLO, Rachele;VILLANI, Vincenzo;
2007

Abstract

For the first time the kinetics of formation of syndiotactic polypropylene mesophase close to 0 8C through differential scanning calorimetry has been investigated. The calorimetric data have been analyzed through the well-known Avrami analysis. We have obtained Avrami coefficients less or at most equal to 2, which are likely to indicate a nearly bidimensionality of the crystallites. The morphology of the mesophase, not known up to now, has been examined through atomic forcemicroscopy (AFM): lamellar structures have been observed. The fractal dimension of the AFM images has been evaluated through the box counting method. It resulted about 2, in a very good agreement with the calculated Avrami coefficients. An infrared and diffractometer analysis on samples kept for increasing times at 0 8C has also been performed to confirm the calorimetric data. The experimental results allow one to better clarify the kinetics of mesophase-formation. It has been found that a time of 3 h at 0 8C is actually necessary for the complete crystallization of the trans-planar mesophase, a longer time is needed to stabilize the mesophase domains when the sample is extracted from 0 8C at room temperature
File in questo prodotto:
File Dimensione Formato  
mesosindio07.pdf

non disponibili

Tipologia: Documento in Post-print
Licenza: DRM non definito
Dimensione 413.42 kB
Formato Adobe PDF
413.42 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11563/16613
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact