| Titre : | Polypropylene and ethylene-propylene copolymer reactor alloys prepared by metallocene/ziegler-natta hybrid catalyst (2010) |
| Auteurs : | Lie Lu, Auteur ; Hong Fan, Auteur ; Bo-Geng Li, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Industrial & engineering chemistry research (Vol. 48 N° 18, Septembre 2009) |
| Article en page(s) : | pp. 8349–8355 |
| Note générale : | Chemical engineering |
| Langues : | Anglais |
| Tags : | Polypropylene Ethylene− ; propylene rubber reactor Propylene homopolymerization Metallocene activation copolymerization |
| Résumé : | Polypropylene/ethylene−propylene rubber (PP/EPR) reactor alloys were prepared with a metallocene/Ziegler−Natta hybrid catalyst system (rac-Et(Ind)2ZrCl2/TiCl4/MgCl2) using a process composed of three stages: propylene homopolymerization, metallocene activation, and ethylene−propylene copolymerization. A series of alloy samples were produced and characterized at various copolymerization conditions by varying the methylaluminoxane (MAO)/Zr ratio and monomer composition. It was shown that the metallocene/Ziegler−Natta hybrid system exhibited the features of both metallocene and Ziegler−Natta catalysts during copolymerization. The hybrid catalyst had better ability in incorporating α-olefin than the Ziegler−Natta catalyst owing to the action of metallocene active sites. DSC and IR analyses suggested that EPR in the alloys became random with increased MAO/Zr ratio. In addition, reducing the ethylene content in the feed decreased the activity and promoted the production of random copolymers. An operation window of reaction conditions was identified for the preparation of well-dispersed spherical PP/EPR reactor alloy particles containing up to about 40 wt % EPR. |
| En ligne : | http://pubs.acs.org/doi/abs/10.1021/ie900579h |
