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Titolo:
REGIOSPECIFICITY AND STEREOSPECIFICITY IN PROPENE POLYMERIZATION WITHMGCL2-SUPPORTED ZIEGLER-NATTA CATALYSTS - EFFECTS OF HYDROGEN AND THEEXTERNAL DONOR
Autore:
CHADWICK JC; VANKESSEL GMM; SUDMEIJER O;
Indirizzi:
AMSTERDAM SHELL RES BV,KONINKLIJKE SHELL LAB,BADHUISWEG 3 1031 CM AMSTERDAM NETHERLANDS
Titolo Testata:
Macromolecular chemistry and physics
fascicolo: 5, volume: 196, anno: 1995,
pagine: 1431 - 1437
SICI:
1022-1352(1995)196:5<1431:RASIPP>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
ALKOXYSILANE DONORS; PROPYLENE; SYSTEM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
15
Recensione:
Indirizzi per estratti:
Citazione:
J.C. Chadwick et al., "REGIOSPECIFICITY AND STEREOSPECIFICITY IN PROPENE POLYMERIZATION WITHMGCL2-SUPPORTED ZIEGLER-NATTA CATALYSTS - EFFECTS OF HYDROGEN AND THEEXTERNAL DONOR", Macromolecular chemistry and physics, 196(5), 1995, pp. 1431-1437

Abstract

Investigation of the effects of hydrogen and different external donors on the stereoregularity and chain-end distribution of polypropylene prepared using MgCl2/TiCl4/phthalate ester-AlEt(3)-alkoxysilane catalyst systems has not only confirmed the importance of regiospecificity in relation to hydrogen activation but has also indicated a significanteffect of stereospecificity. Alkoxysilanes giving high isospecificityalso give high molecular weight polypropylene. Polymer stereoregularity also increases with increasing hydrogen concentration in polymerization. These effects indicate that not only regioirregular but also stereoirregular insertion slows down chain propagation. In each case the probability of chain transfer with hydrogen is higher than that following a stereoregular insertion, and in each case chain transfer with hydrogen leads to the regeneration of isospecific propagation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/08/20 alle ore 21:04:50