| Titre : |
Structure development in injection molding of isotactic polypropylene, its blends, compounds and dynamic vulcanizates |
| Type de document : |
texte imprimé |
| Auteurs : |
Y. Yu, Auteur ; J. L. White, Auteur |
| Année de publication : |
2003 |
| Article en page(s) : |
p. 388-397 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Index. décimale : |
668.9 Polymères |
| Résumé : |
MOLDING - We make a comparative study of structure development in injection molding of isotactic polypropylene, polypropylene blends/compounds and dynamically vulcanized polypropylene thermoplastic elastomers (TPVs) WAXS 2θ scans were used to determine crystalline forms and the distribution of relative amounts of crystalline forms through the cross-section of injection molded parts. WAXS film patterns, polarized optical light micrographs and birefringence were used to qualitatively indicate polymer chain orientation variation through the cross-section. We also used WAXS pole figures to investigate polymer crystalline orientation and filler orientation in different layers of the injection molded parts.
It was found that a low or modest orientation layer exists on the part surface. There is an intermediate highly oriented layer in the parts of isotactic polypropylene and most polypropylene blends/compounds. The interior of the parts was spherulitic and increasingly isotropic as one moved to the center. The thickness of the surface layer increases as the injection pressure decreases. The layer was not observed in parts of dynamically vulcanized polypropylene thermoplastic elastomers. This would seem to be associated with the TPVs possessing a yield stress and not exhibiting substantial fountain flow in mold filling. |
| Note de contenu : |
- EXPERIMENTAL : Materials - Shear viscosity - Injection molding - Methods used to cut thin slices - Birefringence and polarized light optical photo micrographs - Wide angle X-ray diffraction 2o scans - Wide angle X-ray diffraction film patterns and pole figures
- RESULTS : Identification of crystalline modifications - WAXS film patterns - Polarized light optical micrographs - Birefringence - WAXS pole figures
- DISCUSSION : Fluide mechanics of mold filling of thermoplastics melts of PP, blends, compounds and TPVs - Energy balance and melt solidification - Formation of b-crystals in injection molded parts - Influence of oriented talc discs on PP crystallographic axis orientation |
| DOI : |
10.3139/217.1786 |
| En ligne : |
https://drive.google.com/file/d/1tFoY5TWIgvIondiZMqhxu09-MWiFeEgx/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15823 |
in INTERNATIONAL POLYMER PROCESSING > Vol. XVIII, N° 4 (12/2003) . - p. 388-397
Aller sur edunet
Accueil
Structure development in injection molding of isotactic polypropylene, its blends, compounds and dynamic vulcanizates in INTERNATIONAL POLYMER PROCESSING, Vol. XVIII, N° 4 (12/2003)
