ISSN:
1434-4475
Keywords:
Catalytic hydrogenation
;
Coordination polymerization
;
Glass transition temperature
;
1,4-Poly(2,3-dimethylbutadiene), cis- and trans-
;
Polymers
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Zusammenfassung Kopf-zu-Kopf-Polypropylen wurde mittels katalytischer Hydrierung voncis-1,4-Poly(2,3-dimethylbutadien) bzw.trans-1,4-Poly(2,3-dimethylbutadien) mit Kobalt-2-ethylhexanoat/Triethyl-aluminium als Katalysator dargestellt. Die Hydrierung verlief überwiegend übercis-Addition, war aber nicht stereospezifisch. Die Polymerproben wurden mittels IR und NMR, insbesondere13C, charakterisiert. Die erhaltenen Polymeren waren amorph und zeigten Glasübergangstemperaturen, die um etwa 20°C niedriger waren als bei Kopf-zu-Schwanz-Polypropylen. Die thermische Stabilität von Kopf-zu-Kopf-Polypropylen ist nicht signifikant verschieden von ataktischem oder isotaktischem Kopf-zu-Schwanz-Polypropylen.
Notes:
Abstract Head to head polypropylene was prepared by catalytic hydrogenation of eithercis-1,4-poly(2,3-dimethylbutadiene) ortrans-1,4-poly(2,3-dimethylbutadiene) with cobalt 2-ethylhexanoate/triethylaluminium as the hydrogenation catalyst in decahydronaphthalene solution. The hydrogenation occurred predominantly bycis hydrogen addition, but was not stereospecific. The samples of head to head polypropylene were characterized by IR and NMR, particularly by13C-NMR spectroscopy. The polymers were amorphous and exhibited glass transition temperatures about 20°C lower than that of head to tail poly-propylene; the glass transition temperatures were measured by DSC and varied somewhat from sample to sample (sufficiently high molecular weight) according to their stereochemistry. TheT gvalues were confirmed by Rheovibron measurements. The thermal stability of head to head polypropylene is not significantly different from that of either atactic or isotactic head to tail polypropylene.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00904681
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