MOLECULAR WEIGHT DISTRIBUTION ANALYSIS FOR ETHYLENE-VINYL ALCOHOL COPOLYMER RESIN

摘要

PURPOSE:To enable accurate measurement by introducing a dimethylformamide DMF solution of an ethylene-vinyl alcohol copolymer resin into a mobile phase comprising DMF to performing a gel permeation chromatography thereof. CONSTITUTION:An ethylene-vinyl alcohol copolymer resin (sample) is dissolved by heat using DMF and a gel permeation chromatography GPC using the DMF as eluent is performed and the sample is detected with a differential refractometer 6 to measure a molecular weight distribution of the sample. In the GPC, for example, a solution in which the sample to be analyzed is dissolved in a mobile-phase solvent is applied to a column 4 using a porous stylene-divinyl benzene based polymer spherical fine perticle as packing agent to separate the sample in terms of sizes of molecules in the order of larger molecules and the weight of the sample molecule is analyzed. Then, a molecular weight distribution of the sample can be determined. The DMF is used as identical in the mobile phase to the dissolving solution of the sample and the GPC thereby enabling efficient measurement of a molecular weight distribution.