High-temperature two-dimensional liquid chromatography of ethylene-vinylacetate copolymers.
Temperature rising elution fractionation hyphenated to size exclusion chromatography (TREF×SEC) is a routine technique to determine the chemical heterogeneity of semicrystalline olefin copolymers. Its applicability is limited to well crystallizing samples. High-temperature two-dimensional liquid chromatography, HT 2D-LC, where the chromatographic separation by HPLC is hyphenated to SEC (HPLC×SEC) holds the promise to separate such materials irrespective of their crystallizability. A model blend consisting of ethylene-vinyl acetate (EVA) copolymers covering a broad range of chemical composition distribution including amorphous and semicrystalline copolymers and a polyethylene standard was separated by HT 2D-LC at 140°C. Both axes of the contour plot, i.e. the compositional axis from the HPLC and the molar mass axis from the SEC separation were calibrated for the first time. Therefore, a new approach to determine the void and dwell volume of the developed HT 2D-LC instrument was applied. The results from the HT 2D-LC separation are compared to those from a cross-fractionation (TREF×SEC) experiment.
Ginzburg
Anton
A
Deutsches Kunststoff-Institut, Schlossgartenstr. 6, 64289 Darmstadt, Germany. AGinzburg@dki.tu-darmstadt.de
Macko
Tibor
T
Dolle
Volker
V
Brüll
Robert
R
D002850:Chromatography, Gel / Q000295:instrumentation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003512:Cyclohexanones / Q000737:chemistry; D008956:Models, Chemical; D020959:Polyethylene / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry*; D013696:Temperature
D003512:Cyclohexanones; D011145:Polyvinyls; C016438:ethylenevinylacetate copolymer; C036468:cyclohexanone; D020959:Polyethylene