Mc. Murray et Mc. Baird, Copolymerization of 1-hexene and ethylene catalyzed by the Ziegler catalyst Cp*TiMe3/B(C6F5)(3), J POL SC PC, 38(21), 2000, pp. 3966-3976
Citations number
80
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
The Ziegler-Natta system Cp*TiMe3/B(C6F5)(3) catalyzed the copolymerization
of ethylene and 1-hexene in toluene into materials that were characterized
by H-1 and C-13{H-1} NMR spectroscopy, differential scanning calorimetry,
and gel permeation chromatography. The effects of temperature and ethylene/
1-hexene and olefin/catalyst ratios on catalyst activities and copolymer mo
lecular weights and molecular weight distributions were studied; the ethyle
ne proportions varied from less than 5% to 85% or more. In addition, signif
icant amounts of 1-hexene were incorporated into the growing polymer chain
in a 2,1-fashion; consequently, conventional C-13 NMR analytical methodolog
ies for deducing monomer proportions and dispersions and polymer microstruc
tures, based on a low 1,2-incorporation of ol-olefin, did not work very wel
l. A soluble (in toluene at ambient temperature) but very high molecular we
ight (weight-average molecular weight similar to 8 x 10(5), weight-average
molecular weight/number-average molecular weight = 1.8) rubbery copolymer t
hat formed at -78 degrees C exhibited a predominantly alternating microstru
cture. (C) 2000 John Wiley & Sons, Inc.