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- Title
Study of the compositional heterogeneity of ethylene/1-hexene copolymers produced over supported catalysts of different composition.
- Authors
Matsko, Mikhail A.; Echevskaya, Ludmila G.; Vanina, Marina P.; Nikolaeva, Marina I.; Mikenas, Tatyana B.; Zakharov, Vladimir A.
- Abstract
Separation into narrow MWD fractions (liquid-liquid fractionation) and preparative TREF (temperature rising elution fractionation) with subsequent analysis of fractions by GPC, FTIR, and 13C NMR spectroscopy were used to study the comonomer distribution of ethylene/1-hexene copolymers produced over highly active supported titanium- and vanadium-magnesium catalysts (TMC and VMC) and a supported zirconocene catalyst. These catalysts produce PE with different MWD: M w/ M n values vary from 2.9 for zirconocene catalyst, 4.0 for TMC, and 15 for VMC. 1-Hexene increases polydispersity to 25 for copolymer produced over VMC and hardly affects MWD of the copolymer produced over TMC and zirconocene catalysts. The most broad short chain branching distribution (SCBD) was found for ethylene/1-hexene copolymers produced over TMC. VMC and supported zirconocene catalyst produce copolymers with uniform profile of SCB content vs. molecular weight in spite of great differences in M w/ M n values (22 and 2.5 respectively). TREF data showed that majority of copolymer produced over supported zirconocene catalyst was eluted at 70-90°C (about 85 wt %). In the case of VMC copolymer's fractions were eluted in the broad temperature interval (40-100°C). Accordingly, TREF data indicate a more homogeneous SCBD in copolymer, produced over supported zirconocene catalyst. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
- Subjects
ETHYLENE; HEXENE; COPOLYMERS; SEPARATION (Technology); LIQUID-liquid interfaces; FOURIER transform infrared spectroscopy; ZIRCONOCENES; MOLECULAR weights
- Publication
Journal of Applied Polymer Science, 2012, Vol 126, Issue 6, p2017
- ISSN
0021-8995
- Publication type
Article
- DOI
10.1002/app.36643