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CRYSTAF Analysis of Polyethylene Synthesized with Phillips Catalyst
Author(s) -
Xia Wei,
Taniike Toshiaki,
Terano Minoru,
Fujitani Tadahiro,
Liu Boping,
Soares João B. P.
Publication year - 2009
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200951110
Subject(s) - cyclopentene , crystallization , copolymer , polyethylene , ethylene , polymer chemistry , fractionation , catalysis , materials science , molar ratio , chemical engineering , molar mass , crystallinity , chemistry , organic chemistry , polymer , composite material , engineering
Crystallization analysis fractionation (CRYSTAF) was used for the first time to investigate the solution crystallization behavior of ethylene homopolymers and copolymers made with Phillips CrO x /SiO 2 catalyst. Interestingly, the crystallization peak temperatures ( T p ) of copolymers of ethylene and cyclopentene increased with increasing cyclopentene molar fraction in the copolymer. Comparing two factors (short chain branches (SCBs) and cyclopentene incorporation), decreasing SCB frequency is proposed as the dominant factor to explain the increase of crystallization peak temperatures with increasing cyclopentene incorporation. In addition, SCB frequency and molecular weight might be the two significant factors determining the crystallization temperature of polyethylene made with Phillips CrO x /SiO 2 catalyst with different cocatalysts (triethylaluminum and diethylaluminum ethoxide).