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Assessment of changes due to accelerated weathering of low - density polyethylene / feather composites / Spiridon Siouris in Industrial & engineering chemistry research, Vol. 51 N° 21 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 21 (Mai 2012) . - pp. 7279-7286 Titre : Assessment of changes due to accelerated weathering of low - density polyethylene / feather composites Type de document : texte imprimé Auteurs : Spiridon Siouris, Auteur ; Oana Maria Paduraru, Auteur ; Marek Rudowski, Auteur Année de publication : 2012 Article en page(s) : pp. 7279-7286 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Composite  material  Density  Material  weathering  Weathering Résumé : In this study, property changes of controlled aged LDPE/feather composites in comparison to those of nonaged samples were investigated by mechanical tests, dynamic rheological and thermal tests, infrared spectroscopy, and oxygen permeability analysis. The viscoelastic behavior of the aged composites was modified, whereas a pseudoplastic character was observed for the nonaged samples. After weathering, infrared spectroscopy indicated the formation of carbonyl and vinyl groups, and the oxygen permeability became significantly higher than for the reference samples. DSC results showed α-helix denaturation of keratin after aging and an increase in crystallinity due to reinforcement of composites containing feather fibers upon UV exposure. An aging time of 500 h was found to induce surface degradation of composites, especially for a feather fiber loading of 10 wt %. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25948469 [article] Assessment of changes due to accelerated weathering of low - density polyethylene / feather composites [texte imprimé] / Spiridon Siouris, Auteur ; Oana Maria Paduraru, Auteur ; Marek Rudowski, Auteur . - 2012 . - pp. 7279-7286. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 21 (Mai 2012) . - pp. 7279-7286 Mots-clés : Composite  material  Density  Material  weathering  Weathering Résumé : In this study, property changes of controlled aged LDPE/feather composites in comparison to those of nonaged samples were investigated by mechanical tests, dynamic rheological and thermal tests, infrared spectroscopy, and oxygen permeability analysis. The viscoelastic behavior of the aged composites was modified, whereas a pseudoplastic character was observed for the nonaged samples. After weathering, infrared spectroscopy indicated the formation of carbonyl and vinyl groups, and the oxygen permeability became significantly higher than for the reference samples. DSC results showed α-helix denaturation of keratin after aging and an increase in crystallinity due to reinforcement of composites containing feather fibers upon UV exposure. An aging time of 500 h was found to induce surface degradation of composites, especially for a feather fiber loading of 10 wt %. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25948469

Thermodynamic properties of pentaerythritol - based species involved in degradation of aviation gas turbine lubricants / Spiridon Siouris in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12294–12301 Titre : Thermodynamic properties of pentaerythritol - based species involved in degradation of aviation gas turbine lubricants Type de document : texte imprimé Auteurs : Spiridon Siouris, Auteur ; Christopher W. Wilson, Auteur Année de publication : 2011 Article en page(s) : pp. 12294–12301 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamic  Gas  Turbine  Lubricants Résumé : The work in this Article deals with the estimation of thermodynamic data for the major species found during lubricant degradation. The organic group R on which the species were based was the pentaerythritol molecule. A computer code was developed that utilizes zero-order and bond additivity methods for the estimation of thermodynamic properties. The validation of the code was carried out against thermodynamic data for species found in published databases and showed that the computed values for heat capacity, enthalpy, and entropy were in close agreement with the reference values. Having gained confidence in the reliability of the developed code, the thermodynamic properties of species involved in aviation gas turbine lubricants were estimated and are presented in this Article. This work is the first part toward a study for the development of a lubricant degradation model in which the changes in the thermodynamic properties, and therefore heat transfer, due to chemical reactions are accounted for. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101236n [article] Thermodynamic properties of pentaerythritol - based species involved in degradation of aviation gas turbine lubricants [texte imprimé] / Spiridon Siouris, Auteur ; Christopher W. Wilson, Auteur . - 2011 . - pp. 12294–12301. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12294–12301 Mots-clés : Thermodynamic  Gas  Turbine  Lubricants Résumé : The work in this Article deals with the estimation of thermodynamic data for the major species found during lubricant degradation. The organic group R on which the species were based was the pentaerythritol molecule. A computer code was developed that utilizes zero-order and bond additivity methods for the estimation of thermodynamic properties. The validation of the code was carried out against thermodynamic data for species found in published databases and showed that the computed values for heat capacity, enthalpy, and entropy were in close agreement with the reference values. Having gained confidence in the reliability of the developed code, the thermodynamic properties of species involved in aviation gas turbine lubricants were estimated and are presented in this Article. This work is the first part toward a study for the development of a lubricant degradation model in which the changes in the thermodynamic properties, and therefore heat transfer, due to chemical reactions are accounted for. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101236n