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Periodic switching of monomer additions for controlling the compositions and microstructures of segmented and random ethylene-propylene copolymers in polypropylene in-reactor alloys / Zhou Tian in Industrial & engineering chemistry research, Vol. 50 N° 10 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 5992-5999 Titre : Periodic switching of monomer additions for controlling the compositions and microstructures of segmented and random ethylene-propylene copolymers in polypropylene in-reactor alloys Type de document : texte imprimé Auteurs : Zhou Tian, Auteur ; Xue-Ping Gu, Auteur ; Gang-Liang Wu, Auteur Année de publication : 2011 Article en page(s) : pp. 5992-5999 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactor  Microstructure Résumé : This work aims at shading fundamental insights into mechanisms that dictate the composition and microstructure of polypropylene/poly(ethylene-co-propylene) (PP/EPR) in-reactor alloys produced by the multizone circulating reactor (MZCR) technology, a novel one for polyolefin production. For this purpose, this technology is simulated by a batch process with periodic switching of monomer additions. An increase in the switch frequency leads to a decrease in the fraction of ethylene/propylene random (amorphous) copolymers denoted as EPR and an increase in the fraction and the length of PP segments of ethylene/ propylene segmented (partially crystalline) copolymers denoted as EPS. Concomitantly, the size of the dispersed phase domains (EPR) decreases, and its size distribution becomes more uniform as a result of the decrease in the fraction of the EPR and the increase in that of the EPS which acts as a compatibilizer for PP/EPR in-reactor blends. Mechanical properties of the PP/EPR in-reactor blends are also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24158896 [article] Periodic switching of monomer additions for controlling the compositions and microstructures of segmented and random ethylene-propylene copolymers in polypropylene in-reactor alloys [texte imprimé] / Zhou Tian, Auteur ; Xue-Ping Gu, Auteur ; Gang-Liang Wu, Auteur . - 2011 . - pp. 5992-5999. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 5992-5999 Mots-clés : Reactor  Microstructure Résumé : This work aims at shading fundamental insights into mechanisms that dictate the composition and microstructure of polypropylene/poly(ethylene-co-propylene) (PP/EPR) in-reactor alloys produced by the multizone circulating reactor (MZCR) technology, a novel one for polyolefin production. For this purpose, this technology is simulated by a batch process with periodic switching of monomer additions. An increase in the switch frequency leads to a decrease in the fraction of ethylene/propylene random (amorphous) copolymers denoted as EPR and an increase in the fraction and the length of PP segments of ethylene/ propylene segmented (partially crystalline) copolymers denoted as EPS. Concomitantly, the size of the dispersed phase domains (EPR) decreases, and its size distribution becomes more uniform as a result of the decrease in the fraction of the EPR and the increase in that of the EPS which acts as a compatibilizer for PP/EPR in-reactor blends. Mechanical properties of the PP/EPR in-reactor blends are also discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24158896