Titre : |
Film casting of polycarbonate/multi-walled carbon nanotubes composites using ultrasound-assisted twin-screw extruder: experiment and simulation |
Type de document : |
texte imprimé |
Auteurs : |
Xiang Gao, Auteur ; Avraam I. Isayev, Auteur |
Année de publication : |
2022 |
Article en page(s) : |
p. 357-371 |
Note générale : |
Bibliogr. |
Langues : |
Anglais (eng) |
Catégories : |
Composites à fibres -- Extrusion Composites à fibres de carbone Essais (technologie) Films plastiques Nanotubes de carbone à parois multiplesUn nanotube de carbone multifeuillet est constitué de plusieurs feuillets de graphènes enroulés les uns autour des autres. Il existe deux modèles pour décrire la structure des nanotubes multifeuillets :
- le modèle poupée russe: les plans de graphène sont arrangés en cylindres concentriques ;
- le modèle parchemin: un seul feuillet de graphène est enroulé sur lui-même, comme une feuille de papier. Polycarbonates Viscosité élongationnelleLa viscosité élongationnelle est la viscosité apparaissant lorsqu’une contrainte élongationnelle est appliquée au fluide. (Wikipedia)
|
Index. décimale : |
668.4 Plastiques, vinyles |
Résumé : |
A one-step ultrasonic film casting process to manufacture nanocomposite films was developed, in which polycarbonate (PC) was mixed with multi-walled carbon nanotubes (CNT) and cast into films in one process. Numerical and experimental investigations of necking phenomenon were carried out for film casting of PC/CNT composites. Experimental results revealed that the necking along film line decreased with imposition of ultrasound and increasing CNT content, indicating that incorporation of CNT and imposition of ultrasound restrained the elongational flow behavior of melt, resulting in film of a larger width. Isothermal and nonisothermal numerical simulations of the process were performed. In isothermal simulations, the polymer melt was assumed to be maintained at the die temperature. In nonisothermal simulations, the temperature change along the film line was determined from heat transfer calculations with the WLF temperature-dependent viscosity. The simulated and experimental results on normalized film width, defined as a ratio of cast film width to die width, as a function of the distance from the die at various extension ratios were compared. The comparison indicated that changes in film width and thickness along the stretching direction in the nonisothermal process were in better agreement with experimental results than that in the isothermal process. Both experimental and simulated results showed a decrease of film width with take-up speed. Due to the presence of edge effect, the film width in experiment was lower than the simulated one. With incorporation of CNT, a better agreement between experimental and simulated results was obtained, due to a reduced edge effect in the film. |
Note de contenu : |
- EXPERIMENTAL : Materials - Preparation of PC/CNT nanocomposite films - Testing
- RESULTS AND DISCUSSION : Processing characteristics - Necking phenomenon during film casting - Mechanical properties
- NUMERICAL SIMULATION OF THE FILM CASTING PROCESS : Isothermal simulation - Non-isothermal simulation
- Table 1 : Parameters used in film casting simulation
- Table 2 : Elongational viscosity of PC/CNT composites |
DOI : |
https://doi.org/10.1515/ipp-2021-4200 |
En ligne : |
https://drive.google.com/file/d/1l5bi0RCPdWKDKFcbCnAXkY18HhEQ806J/view?usp=shari [...] |
Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37912 |
in INTERNATIONAL POLYMER PROCESSING > Vol. 37, N° 4 (2022) . - p. 357-371