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Catalytic effects of nickel (Cobalt or Zinc) acetates on thermal and flammability properties of polypropylene-modified lignin composites / Youming Yu in Industrial & engineering chemistry research, Vol. 51 N° 38 (Septembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 38 (Septembre 2012) . - pp. 12367-12374 Titre : Catalytic effects of nickel (Cobalt or Zinc) acetates on thermal and flammability properties of polypropylene-modified lignin composites Type de document : texte imprimé Auteurs : Youming Yu, Auteur ; Ping’an Song, Auteur ; Chunde Jin, Auteur Année de publication : 2012 Article en page(s) : pp. 12367-12374 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Composite  material  Flammability  Catalytic  reaction Résumé : Previous work has demonstrated that functionalized lignin (PN-lignin) was shown to enhance thermal stability and flame retardancy of polypropylene (PP). To further strength these effects, nickel (cobalt or zinc) acetates were introduced into PP/PN-lignin systems in the present work. Thermogravimetric analysis demonstrates that adding 2 wt % nickel acetate (Ni(Ac)2) catalytically degrades PP/PN-lignin but significantly increases the char residues in both N2 and air conditions. For instance, the presence of Ni2+ reduced the initial degradation temperature (T,) by ∼13 °C but doubled the char residue in the N2 condition relative to those of PP/PN-lignin. In comparison, the addition of cobalt or zinc acetate has little effect on thermal properties and char residues of PP/PN-lignin. Cone calorimeter results indicate that although the presence of Ni(Ac)2 shortens slightly the time to ignition (tign) from ∼38 s to ∼31 s, it reduces the peak heat release rate (PHRR) from 380 kW/m2 to 330 kW/m2, suggesting a further improved flame retardancy of PP/PN-lignin. Moreover, the addition of Ni(Ac)2 significantly increases char residue by ∼44%. Limited oxygen index (LOI) measurements show that adding Ni(Ac)2 increases the LOI value from 22 for PP/PN-lignin (17.5 for pure PP) up to 26, also indicating a better flame retardancy. Unlike Ni(Ac)2, cobalt or zinc acetate still has no obvious effect on flame retardancy. Char residue analysis shows that not only does Ni(Ac)2 participate in the char-forming process of PN-lignin by itself but its degradation products, NiO and Ni(0), also promote the carbonization through the catalytic action of the PP matrix, both of which are primarily responsible for the enhanced flame retardancy of the PP/PN-lignin system. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26399688 [article] Catalytic effects of nickel (Cobalt or Zinc) acetates on thermal and flammability properties of polypropylene-modified lignin composites [texte imprimé] / Youming Yu, Auteur ; Ping’an Song, Auteur ; Chunde Jin, Auteur . - 2012 . - pp. 12367-12374. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 38 (Septembre 2012) . - pp. 12367-12374 Mots-clés : Composite  material  Flammability  Catalytic  reaction Résumé : Previous work has demonstrated that functionalized lignin (PN-lignin) was shown to enhance thermal stability and flame retardancy of polypropylene (PP). To further strength these effects, nickel (cobalt or zinc) acetates were introduced into PP/PN-lignin systems in the present work. Thermogravimetric analysis demonstrates that adding 2 wt % nickel acetate (Ni(Ac)2) catalytically degrades PP/PN-lignin but significantly increases the char residues in both N2 and air conditions. For instance, the presence of Ni2+ reduced the initial degradation temperature (T,) by ∼13 °C but doubled the char residue in the N2 condition relative to those of PP/PN-lignin. In comparison, the addition of cobalt or zinc acetate has little effect on thermal properties and char residues of PP/PN-lignin. Cone calorimeter results indicate that although the presence of Ni(Ac)2 shortens slightly the time to ignition (tign) from ∼38 s to ∼31 s, it reduces the peak heat release rate (PHRR) from 380 kW/m2 to 330 kW/m2, suggesting a further improved flame retardancy of PP/PN-lignin. Moreover, the addition of Ni(Ac)2 significantly increases char residue by ∼44%. Limited oxygen index (LOI) measurements show that adding Ni(Ac)2 increases the LOI value from 22 for PP/PN-lignin (17.5 for pure PP) up to 26, also indicating a better flame retardancy. Unlike Ni(Ac)2, cobalt or zinc acetate still has no obvious effect on flame retardancy. Char residue analysis shows that not only does Ni(Ac)2 participate in the char-forming process of PN-lignin by itself but its degradation products, NiO and Ni(0), also promote the carbonization through the catalytic action of the PP matrix, both of which are primarily responsible for the enhanced flame retardancy of the PP/PN-lignin system. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26399688

Permeability, viscoelasticity, and flammability performances and their relationship to polymer nanocomposites / Ping’an Song 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. 7255-7263 Titre : Permeability, viscoelasticity, and flammability performances and their relationship to polymer nanocomposites Type de document : texte imprimé Auteurs : Ping’an Song, Auteur ; Youming Yu, Auteur ; Tao Zhang, Auteur Année de publication : 2012 Article en page(s) : pp. 7255-7263 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanocomposite  Flammability  Viscoelasticity  Permeability Résumé : Despite abundant studies on gas barrier, viscoelastic, and flammability properties of polymer nanocomposites, comprehensive understandings of these performances and their relationships are still lacking. We herein attempt to gain deep insights into the performances by creating several polymer nanocomposites by incorporating three types of nanoparticles, nanoclay (Clay), carbon nanotubes (CNTs), and reduced graphene nanoplates (RGO), into polypropylene (PP). The oxygen permeability, viscoelasticity, and flammability measurements demonstrate that RGO can lead to much more reduction in the gas permeability (by ∼73%) and flammability (peak heat release rate (PHRR) reduction by ∼78%), as well as a higher storage modulus and melt viscosity of polymer matrix relative to clay and CNTs at the same loading (1.0 wt %) due to its higher aspect ratio. Clay performs better than CNTs in terms of gas barrier property due to its lamellar structure while behaves worse than CNTs in terms of increasing the melt viscosity and reducing flammability of polymers. Most important, there is a nearly line correlation among these properties for all polymer nanocomposites despite some deviations. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25948466 [article] Permeability, viscoelasticity, and flammability performances and their relationship to polymer nanocomposites [texte imprimé] / Ping’an Song, Auteur ; Youming Yu, Auteur ; Tao Zhang, Auteur . - 2012 . - pp. 7255-7263. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 21 (Mai 2012) . - pp. 7255-7263 Mots-clés : Nanocomposite  Flammability  Viscoelasticity  Permeability Résumé : Despite abundant studies on gas barrier, viscoelastic, and flammability properties of polymer nanocomposites, comprehensive understandings of these performances and their relationships are still lacking. We herein attempt to gain deep insights into the performances by creating several polymer nanocomposites by incorporating three types of nanoparticles, nanoclay (Clay), carbon nanotubes (CNTs), and reduced graphene nanoplates (RGO), into polypropylene (PP). The oxygen permeability, viscoelasticity, and flammability measurements demonstrate that RGO can lead to much more reduction in the gas permeability (by ∼73%) and flammability (peak heat release rate (PHRR) reduction by ∼78%), as well as a higher storage modulus and melt viscosity of polymer matrix relative to clay and CNTs at the same loading (1.0 wt %) due to its higher aspect ratio. Clay performs better than CNTs in terms of gas barrier property due to its lamellar structure while behaves worse than CNTs in terms of increasing the melt viscosity and reducing flammability of polymers. Most important, there is a nearly line correlation among these properties for all polymer nanocomposites despite some deviations. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25948466