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Nyambeni Luruli Thijs Pijpers Robert Brüll Valérie Grumel Harald Pasch Vincent Mathot 《Journal of Polymer Science.Polymer Physics》2007,45(21):2956-2965
The short chain branching distribution (SCBD) and thermal properties of ethylene/1‐pentene copolymers were studied using SEC‐FTIR and SEC‐HPer DSC. The copolymers, synthesized with Cp2ZrCl2/MAO, were fractionated using size exclusion chromatography (SEC). The infrared analysis of the fractions showed that the copolymers had—on average—higher 1‐pentene concentration in the low molecular weight range. Furthermore, the thermal properties of the SEC deposits of these copolymers on a Germanium disc were studied using high performance differential scanning calorimetry (HPer DSC). Single SEC separations were used to accumulate fractions in the microgram range that were directly analyzed with regard to their thermal properties, thus allowing us to study SCBD as well as thermal behavior simultaneously. When these fractions (with masses ranging from 10–80 μg) were analyzed using HPer DSC, good melting and crystallization temperature distributions were obtained, proving that HPer DSC can be used as a complementary method to SEC‐FTIR. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2956–2965, 2007 相似文献
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Nyambeni Luruli Valrie Grumel Robert Brüll Aletta du Toit Harald Pasch Albert J. van Reenen Helgard G. Raubenheimer 《Journal of polymer science. Part A, Polymer chemistry》2004,42(20):5121-5133
Ethylene/1‐pentene copolymers were prepared using a [(CO)5W= C(Me)OZr(Cp)2Cl] (1)/MAO catalyst system. 1‐Pentene incorporation in the copolymer was monitored using 13C‐NMR spectroscopic methods. The weight average molecular weights (Mw) of the copolymers were between 142,000 and 629,000 g/mol, with polydispersity indexes (PDIs) ranging from ≈ 2 to 90, as analyzed by size exclusion chromatography (SEC). Melting and crystallization temperatures, determined using differential scanning calorimetry (DSC) and crystallization analysis fractionation (CRYSTAF), decreased linearly as the amount of 1‐pentene in the copolymer increased. SEC‐FTIR revealed that the 1‐pentene is predominantly incorporated in the low molecular weight fraction. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5121–5133, 2004 相似文献
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