title: Separation of bimodal high density polyethylene using multidimensional high temperature liquid chromatography.
abstract: High-temperature two-dimensional liquid chromatography (HT 2D-LC) using HT-HPLC as first dimension and HT-SEC as second dimension holds enormous potential to investigate the distribution according to molar mass and chemical composition of bimodal high density polyethylene (BiHDPE), as it avoids drawbacks of crystallization-based techniques. In this study, we have stepwise optimized the chromatographic parameters of 1D, comprising gradient slope and temperature, using model homo- and copolymers of ethylene with the aim to minimize the impact of molar mass on the compositional separation. Then the HT-HPLC was hyphenated to HT-SEC and optimum conditions for the volume of the sample transfer loop were probed with regard to the resolution of BiHDPE into the individual constituents HDPE and LLDPE. A particular important aspect was the use of infrared (IR) detection, and the demands it puts on the chromatographic aspects: We have shown that IR detection can be successfully applied in HT 2D-LC of BiHDPE, which is broadly distributed with regard to short chain branching and molar mass, only when the separation in 2D is optimized with regard to chromatographic resolution. As final result a bimodality is evident in the contour and the 3D surface plots as well as in both HPLC and SEC projections generated from HT 2D-LC.
authors.affiliation: Fraunhofer Institute for Structural Durability and System Reliability, Division Plastics, Group Material Analytics, Schlossgartenstrasse 6, 64289 Darmstadt, Germany.
authors.forename: K N
authors.initials: KN
authors.lastname: Prabhu
authors.affiliation: Fraunhofer Institute for Structural Durability and System Reliability, Division Plastics, Group Material Analytics, Schlossgartenstrasse 6, 64289 Darmstadt, Germany. Electronic address: robert.bruell@lbf.fraunhofer.de.
authors.forename: R
authors.initials: R
authors.lastname: Brüll
authors.affiliation: Fraunhofer Institute for Structural Durability and System Reliability, Division Plastics, Group Material Analytics, Schlossgartenstrasse 6, 64289 Darmstadt, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Macko
authors.affiliation: SABIC Technology & Innovation, STC Geleen, P.O. Box 319, 6160 AH Geleen, The Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Remerie
authors.affiliation: SABIC Technology & Innovation, STC Geleen, P.O. Box 319, 6160 AH Geleen, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Tacx
authors.affiliation: SABIC Technology & Innovation, STC Geleen, P.O. Box 319, 6160 AH Geleen, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Garg
authors.affiliation: SABIC Technology & Innovation, STC Geleen, P.O. Box 319, 6160 AH Geleen, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Ginzburg
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006358:Hot Temperature; D008970:Molecular Weight; D020959:Polyethylene / Q000302:isolation & purification*
chemical_list: D020959:Polyethylene
keywords: Bimodal HDPE; Copolymers; ESCR; HPLC; HT 2D-LC; IR-detector