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Rheological Features and Flow‐Induced Crystallization of Branched Poly[ethylene‐ co ‐(1,4‐cyclohexanedimethylene terephthalate)] Copolyesters
Author(s) -
Quintana Robert,
de Ilarduya Antxon Martínez,
Guerra Sebastián Muñoz,
Fernández Mercedes,
Muñoz María Eugenia,
Santamaría Anton
Publication year - 2008
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.200800152
Subject(s) - materials science , rheology , poly ethylene , crystallization , ethylene , polymer chemistry , chemical engineering , polymer science , flow (mathematics) , composite material , organic chemistry , catalysis , chemistry , engineering , geometry , mathematics
A set of amorphous poly[ethylene‐ co ‐(1,4‐cyclohexanedimethylene terephthalate)] (PECT) copolymers containing 25 and 30% of 1,4‐cyclohexane dimethylene (CHDM) units and small amounts of branching agent pentaerythritol (PER) is investigated. The level of long chain branching was estimated by analyzing the positive deviation from $\eta _0 \sim\overline M _{\rm w}^{3.54}$ law. Branching also produced melt elasticity enhancement which is desirable for certain processing methods. Capillary extrusion experiments at 180 °C generated flow‐induced crystallization in PECT containing 25% of CHDM. Crystallization increased with the amount of PER added, which was explained by the favorable effect of branching to increase elongational rate at the entrance of the capillary. Linear and branched PECTs containing 30% of CHDM did not crystallize.