Premium
Thermal Behavior, Structure and Morphology of Propene/Higher 1‐Olefin Copolymers
Author(s) -
Stagnaro Paola,
Costa Giovanna,
Trefiletti Vincenzo,
Canetti Maurizio,
Forlini Fabrizio,
Alfonso Giovanni C.
Publication year - 2006
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200600288
Subject(s) - tacticity , propene , copolymer , crystallization , materials science , polymer chemistry , olefin fiber , methylaluminoxane , morphology (biology) , phase (matter) , polymerization , crystallography , chemical engineering , metallocene , chemistry , polymer , composite material , organic chemistry , catalysis , engineering , genetics , biology
Summary: Propene‐based random copolymers, synthesized with two isospecific methylaluminoxane‐activated ansa ‐zirconocenes and containing even and odd carbon‐numbered higher 1‐olefins, were investigated by DSC and WAXD. Nature and amount of co‐units affect primary and secondary crystallization as well as melting behavior; their role is discussed in the light of microstructural features of the macromolecular chains. The specific role of 1‐olefin comonomers in the development of the γ ‐polymorph was assessed by crystallizing selected samples at relatively high temperatures. A good agreement between the fraction of γ ‐phase calculated from the deconvolution of the DSC melting endotherms and from WAXD analysis was found. The γ ‐phase content nicely correlates with the average length of the isotactic sequences. In the WAXD patterns of some propene/1‐butene copolymers a new reflection at 2 θ ≅ 10°, likely corresponding to the newly discovered trigonal modification of isotactic polypropene, was found.Room temperature WAXD of copolymer M‐PBu7.5 after isothermal crystallization at two different temperatures.