6533b824fe1ef96bd12814f9

RESEARCH PRODUCT

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

Beata MazonWioletta Ochędzan-siodłak

subject

polyethylenechemistry.chemical_classificationChromatographyPolymers and PlasticsChemistryGeneral Chemical Engineeringgel permeation chromatographyMethylaluminoxanemethylaluminoxanesamples preparationsPolymerzirconocene catalystPolyethyleneCatalysisGel permeation chromatographychemistry.chemical_compoundMaterials ChemistrySample preparationMethanolAluminoxane

description

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 PE samples as well as time of sample keeping in the apparatus (dissolution + measurement time) at temp. 142 °C. A method of MAO removing from PE samples, before GPC measurement, based on additional washing of the sample with HF in methanol solution has been proposed. This modification leads 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 . 10 5 g/mol should not exceed 24 h.

https://doi.org/10.14314/polimery.2003.829