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W. Ochędzan-Siodłak, B. Mazoń

Effect of sample preparation on gel permeation chromatography results of determination

of molecular weight of polyethylene obtained with using of zirconocene catalyst

actiyated with methyl aluminoxane

Polimery 2003, No 11-12, 829


Summary

Molecular weights of polyethylene (PE) obtained with using of zirconocene catalyst activated with large excess of methylaluminoxane (MAO) were determined by gel permeation chromatography (GPC) method. It was found that repeatability of the measurements is strongly influenced by MAO remained in FE samples as weli as time of sample keeping in the apparatus (dissolution + measurement time) at temp. 142 °C. A method of MAO removing from FE samples, before GPC measurement, based on additional washing of the sample with HF in methanol solution has been proposed. This modification Ieads to better both authenticity and repeatability of the results. Studies on the influence of time of sample keeping in the apparatus at temp. 142 °C showed that dissolution time of a polymer showing molecular weight up to 3 g/mol should not exceed 24 h.


Keywords: polyethylene, zirconocene catalyst, methylaluminoxane, gel permeation chromatography, samples preparations

W. Ochędzan-Siodłak, B. Mazoń (1.23 MB)
Effect of sample preparation on gel permeation chromatography results of determination of molecular weight of polyethylene obtained with using of zirconocene catalyst actiyated with methyl aluminoxane