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Titolo:
Thermal properties of ethylene/long chain alpha-olefin copolymers producedby metallocenes
Autore:
Starck, P; Lofgren, B;
Indirizzi:
Helsinki Univ Technol, Ctr Polymer Sci, FIN-02151 Espoo, Finland Helsinki Univ Technol Espoo Finland FIN-02151 , FIN-02151 Espoo, Finland
Titolo Testata:
EUROPEAN POLYMER JOURNAL
fascicolo: 1, volume: 38, anno: 2002,
pagine: 97 - 107
SICI:
0014-3057(200201)38:1<97:TPOECA>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
DYNAMIC-MECHANICAL-PROPERTIES; LOW-DENSITY POLYETHYLENES; OCTENE COPOLYMERS; CATALYST SYSTEMS; ZIEGLER-NATTA; ETHYLENE-1-BUTENE COPOLYMERS; ETHYLENE/1-OCTENE COPOLYMERS; MELTING-POINTS; CRYSTALLIZATION; DSC;
Keywords:
ethylene/alpha-olefin copolymers; comonomer composition distribution; metallocene; thermal properties;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Starck, P Helsinki Univ Technol, Ctr Polymer Sci, POB 356, FIN-02151 Espoo, Finland Helsinki Univ Technol POB 356 Espoo Finland FIN-02151 , Finland
Citazione:
P. Starck e B. Lofgren, "Thermal properties of ethylene/long chain alpha-olefin copolymers producedby metallocenes", EUR POLYM J, 38(1), 2002, pp. 97-107

Abstract

Metallocene type copolymers of ethylene with the alpha -olefins 1-octene, 1-tetradecene and 1-octadecene were characterized by dynamic scanning calorimeter (DSC) and by dynamic mechanical analysis (DMA). At a similar comonomer content above 3 mol%, the higher alpha -olefins gave lower melting points, crystallinities and densities than 1-octene. In DSC a separation technique sorting the crystalline sequence lengths of the polymer into groups was applied, and DSC index, DI, which gave a semiquantitative idea of the chemical homogeneity of the comonomer compositional distributions. By DMA the storage modulus as an indicator of stiffness and loss modulus and loss tangent as a measure of the effect of branching on the beta relaxations were studied. The DMA measurements showed the loss modulus maximum to be a more sensitive value than the loss tangent maximum for the characterization of the comonomer distribution. The intensity of the beta\ transition of 1-octadecene did not increase with increasing branching in contrast to the situation for 1-octene and 1-tetradecene copolymers. (C) 2001 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/09/20 alle ore 22:33:16