Free volume and crystallinity of poly(ethylene naphthalate) treated in pressurized carbon dioxide
Författare
Summary, in English
The free volume and crystallization behaviour of poly(ethylene naphthalate) (PEN) treated in pressurized carbon dioxide was studied, using Positron Annihilation Lifetime Spectroscopy (PALS) and Differential Scanning Calorimetry (DSC). PALS probes the values of free volume cavity sizes in materials, thus making it possible to investigate the effect of pressurized carbon dioxide treatment on free volume hole sizes in PEN. The crystallinity and melting behaviour of PEN was analyzed with temperature modulated DSC. We found that the carbon dioxide pressure during treatment of PEN was the prime parameter affecting the value of free volume after the treatment. The free volume sizes were observed to be insensitive to the other two parameters, temperature and time. Increasing the time of the treatment however, increased the crystallinity of PEN. Interestingly, this was not coupled to a decrease in ortho-Positronium intensity as was expected, indicating that positronium may form in the crystalline fraction of the polymer as well as in the amorphous fraction. (C) 2009 Elsevier Ltd. All rights reserved.
Avdelning/ar
Publiceringsår
2010
Språk
Engelska
Sidor
146-152
Publikation/Tidskrift/Serie
Polymer
Volym
51
Issue
1
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Chemical Sciences
Nyckelord
- Positron annihilation
- Supercritical fluids
- Temperature modulated DSC
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 0032-3861