| Titre : |
Clever tool for short cooling : Systematic approach to the selection of nucleating agents |
| Type de document : |
texte imprimé |
| Auteurs : |
Claire Strasser, Auteur |
| Année de publication : |
2018 |
| Article en page(s) : |
p. 45-51 |
| Langues : |
Anglais (eng) |
| Catégories : |
Analyse thermique
Cristallisation
Matières plastiques -- Refroidissement
Polypropylène
|
| Index. décimale : |
668.4 Plastiques, vinyles |
| Résumé : |
The precise prediction of polypropylene’s crystallization behavior is of great economic importance. Not only do important processing parameters – such as mold temperature and time, and therefore productivity – depend on it, but so do the mechanical properties of the manufactured product. DSC measurements are helpful in precisely assessing the influence of different nucleating agents. |
| Note de contenu : |
- Experiments for the crystallization behavior
- Dynamic measurements
- Isothermal crystallization measurements
- From DSC curves to predictions for process optimization
- Fig. 1 : Cooling (bottom) and second heating (top) of pure polypropylene : crystallization peak in the cooling segment at 110 °C and melting peak in the second heating segment at 162 °C
- Fig. 2 : DSC curves of pure PP and PP with different nucleating agents during cooling at 20 K/min : Pure polypropylene (green), polypropylene with NU-100 (yellow) and polypropylene with trisamide
- Fig. 3 : Isothermal crystallization of pure polypropylene at 128°C (dashed curve: temperature ; solid curve : DSC signal) ; The detail excerpt clearly illustrates the marked, broad exothermal crystallization peakthanks to modified scaling
- Fig. 4 : Isothermal crystallization of pure polypropylene at five temperatures between 124°C and 128°C (dashed : temperature, continuous : DSC signal)
- Fig. 5 : Avrami plot for the isothermal crystallization of pure polypropylene at different temperatures. Points are calculated for the conversion rates from 10 to 90 % of the total peak area
- Fig. 6 : Comparison of the measured and calculated crystallization behavior of pure PP: The simulation (lines) on the basis of a one-step reaction according to the Avrami equation is in good agreement with the DSC measuring points (correlation coefficient: 0.998)
- Fig. 7 : The two-step reaction model according to the Avrami equation and an nth order reaction leads to even better concordance (correlation coefficient : 0.999) between simulation (lines) and DSC measurement points (crystallization peaks) : a) pure PP, b) PP with trisamide and c) PP with NU-100
- Fig. 8 : Prediction of the crystallization behavior of the three samples at an isothermal tempera¬ture of 130 °C
- Table 1 : Results of the isothermal crystallization or pure polypropylene and PP with trisamide or NU-100
- Table 2 : Isothermal crystallization results
- Table 3 : Kinetic parameter of the isothermal crystallization or pure PP, PP+trisamide and PP+NU-100, according to a two-step reaction model |
| En ligne : |
https://www.kunststoffe.de/en/_storage/asset/6989120/storage/master/file/3983293 [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31175 |
in KUNSTSTOFFE INTERNATIONAL > Vol. 108, N° 9 (09/2018) . - p. 45-51
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