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Study of cell nucleation in microcellular poly(lactic acid) foamed with supercritical CO2 through a continuous-extrusion process / Laurent M. Matuana in Industrial & engineering chemistry research, Vol. 49 N° 5 (Mars 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2186–2193 Titre : Study of cell nucleation in microcellular poly(lactic acid) foamed with supercritical CO2 through a continuous-extrusion process Type de document : texte imprimé Auteurs : Laurent M. Matuana, Auteur ; Carlos A. Diaz, Auteur Année de publication : 2010 Article en page(s) : pp. 2186–2193 Note générale : Industial Chemistry Langues : Anglais (eng) Mots-clés : Nucleation;  Poly(lactic  acid) Résumé : Using a continuous-extrusion foaming process, this study examined the effect of the processing temperature on the melt viscosity, pressure drop rate, and cell-population density of poly(lactic acid) (PLA) foams. The study was intended to understand the nucleation mechanisms in order to generate microcellular structures in neat PLA in a continuous-extrusion process using CO2 as the blowing agent. Not only did the temperature affect the melt viscosity but also the cell nucleation rate owing to its effect on the pressure drop rate. When processed at high temperature, the melt viscosity decreased and PLA nucleated fewer bubbles, irrespective of the PLA type (amorphous vs semicrystalline), because of the lower pressure drop rate in the system. Conversely, processing at a lower temperature significantly increased the cell nucleation rate for both PLA types owing to the fact that a high melt viscosity induced a high pressure drop rate. The addition of nanoclay allowed both homogeneous and heterogeneous nucleation to occur during the foaming process. The results showed that the processing temperature is a sensible parameter to produce microcellular PLA with cell densities on the order of 109 cells/cm3 and cell sizes of around 10 μm. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9011694 [article] Study of cell nucleation in microcellular poly(lactic acid) foamed with supercritical CO2 through a continuous-extrusion process [texte imprimé] / Laurent M. Matuana, Auteur ; Carlos A. Diaz, Auteur . - 2010 . - pp. 2186–2193. Industial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2186–2193 Mots-clés : Nucleation;  Poly(lactic  acid) Résumé : Using a continuous-extrusion foaming process, this study examined the effect of the processing temperature on the melt viscosity, pressure drop rate, and cell-population density of poly(lactic acid) (PLA) foams. The study was intended to understand the nucleation mechanisms in order to generate microcellular structures in neat PLA in a continuous-extrusion process using CO2 as the blowing agent. Not only did the temperature affect the melt viscosity but also the cell nucleation rate owing to its effect on the pressure drop rate. When processed at high temperature, the melt viscosity decreased and PLA nucleated fewer bubbles, irrespective of the PLA type (amorphous vs semicrystalline), because of the lower pressure drop rate in the system. Conversely, processing at a lower temperature significantly increased the cell nucleation rate for both PLA types owing to the fact that a high melt viscosity induced a high pressure drop rate. The addition of nanoclay allowed both homogeneous and heterogeneous nucleation to occur during the foaming process. The results showed that the processing temperature is a sensible parameter to produce microcellular PLA with cell densities on the order of 109 cells/cm3 and cell sizes of around 10 μm. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9011694