[article]
| Titre : |
Interdependence of hygroscopic polymer characteristics and drying kinetics during desiccant drying and microwave supported drying |
| Type de document : |
texte imprimé |
| Auteurs : |
Oliver Kast, Auteur ; Tobias Schaible, Auteur |
| Année de publication : |
2020 |
| Article en page(s) : |
p. 376-384 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Coefficient de diffusion Un coefficient de diffusion est une grandeur caractéristique du phénomène de diffusion de la matière. Le coefficient de diffusion mesure le rapport entre le flux molaire dû à la diffusion moléculaire, et le gradient de concentration de l'espèce chimique considérée (ou, plus généralement, de la variable d'effort entraînant cette diffusion), comme formulé par la loi de Fick.
Humidité -- Absorption:Eau -- Absorption
Matériaux -- Propriétés hygroscopiques
Micro-ondes
PolyamidesUn polyamide est un polymère contenant des fonctions amides -C(=O)-NH- résultant d'une réaction de polycondensation entre les fonctions acide carboxylique et amine.
Selon la composition de leur chaîne squelettique, les polyamides sont classés en aliphatiques, semi-aromatiques et aromatiques. Selon le type d'unités répétitives, les polyamides peuvent être des homopolymères ou des copolymères.
Polymères
Polymères -- Propriétés thermiques
Polymérisation
Structure moléculaire
|
| Index. décimale : |
668.4 Plastiques, vinyles |
| Résumé : |
Hygroscopic polymers absorb and bind water. If not dried properly, the residual moisture can cause major problems for converting and affect the product quality significantly. Therefore, an effective drying down to an acceptable moisture level is essential for a successful production. Though data sheets give recommendations for drying parameters, these do not consider the actual current moisture up-take of the plastic pellets or the current ambient conditions. This paper investigates the interdependencies of polymer characteristics, like thermal properties and molecular structure, and the drying kinetics of the respective polymers. Tests are carried out with five different polymers on a State-of-the-Art desiccant dryer. The results show that distinctive drying behaviors can be attributed to the molecular structure of the respective plastic. This is reflected by the activation energy according to Arrhenius, the diffusion coefficient and the Flory-Huggins-Parameter, all showing a positive correlation with drying speed and therefore can be used as indicators to estimate drying times. Also, an industrial scale prototype of a microwave enhanced drying system was used to investigate the effect of microwave application on the drying kinetics. Experimental results show potential for reducing the drying times needed, especially for lower temperatures of the drying air and highly hydrophilic plastics. For higher temperatures, however, the prototype could not compete with the state-of-the-art desiccant dryer, due to heat losses and inefficient tubing of the prototype. Considering this, the benefits of microwave application could be shown representatively for polyamide 6 also at higher temperatures. |
| Note de contenu : |
- INTRODUCTION : Water absorption of hygroscopic polymers - Drying mechanisms of current drying systems
- EXPERIMENTAL : Testing materials - Determination of diffusion coefficients - Experimental set-up - Parametric study
- EXPERIMENTAL RESULTS : Drying performance - Effects of microwave application
- CONCLUDING REMARKS |
| DOI : |
https://doi.org/10.3139/217.3940 |
| En ligne : |
https://drive.google.com/file/d/1IfgML_Rufl3kG3uQKCsZPtLrFe1lxk0n/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34696 |
in INTERNATIONAL POLYMER PROCESSING > Vol. XXXV, N° 4 (08/2020) . - p. 376-384
[article]
|
Aller sur edunet
Accueil
Interdependence of hygroscopic polymer characteristics and drying kinetics during desiccant drying and microwave supported drying in INTERNATIONAL POLYMER PROCESSING, Vol. XXXV, N° 4 (08/2020)
