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Evaluation of the fractionated crystallization of isotactic polypropylene and high density polyethylenes in their blends with Cycloolefin copolymers
Author(s) -
Pimbert Sylvie
Publication year - 2003
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.200351330
Subject(s) - differential scanning calorimetry , materials science , crystallization , nucleation , tacticity , polymer blend , polypropylene , high density polyethylene , copolymer , crystallinity , amorphous solid , polymer , dispersity , polymer chemistry , chemical engineering , phase (matter) , polyethylene , composite material , polymerization , chemistry , crystallography , organic chemistry , thermodynamics , physics , engineering
Crystallization of semi‐crystalline polyolefins (i‐polypropylenes and HD‐polyethylenes) in their blends with amorphous cycloolefin copolymers (COC) were studied. The thermal behaviour of the blends was characterized by Differential Scanning Calorimetry (DSC) whereas blend morphologies were investigated by Scanning Electronic Microscopy (SEM). In iPP/COC blends, a phenomenon of fractionated crystallization is evidenced when i‐PP is finely dispersed in the COC matrix. Such a behavior is generally observed when the number of droplets is much larger than the number of heterogeneities originally present in the bulk polymer. In HDPE/COC blends, complex morphologies are observed which do not fit good correlation with DSC results. The nucleation and crystallization modes seem to be largely influenced by the characteristics of the micro‐dispersed phase, largely dependent on the PE molecular weights and polydispersity indices.