Cheruthazhekatt S., Pijpers T.F.J., Harding G.W., Mathot V.B.F., Pasch H.
Multidimensional analysis of the complex composition of impact polypropylene copolymers: Combination of TREF, SEC-FTIR-HPer DSC, and high temperature 2D-LC
Department of Chemistry and Polymer Science, University of Stellenbosch, 7602 Matieland, South Africa; SciTe, Ridder Vosstraat 6, 6162 AX Geleen, Netherlands; Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
Cheruthazhekatt, S., Department of Chemistry and Polymer Science, University of Stellenbosch, 7602 Matieland, South Africa; Pijpers, T.F.J., SciTe, Ridder Vosstraat 6, 6162 AX Geleen, Netherlands, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium; Harding, G.W., Department of Chemistry and Polymer Science, University of Stellenbosch, 7602 Matieland, South Africa; Mathot, V.B.F., SciTe, Ridder Vosstraat 6, 6162 AX Geleen, Netherlands, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium; Pasch, H., Department of Chemistry and Polymer Science, University of Stellenbosch, 7602 Matieland, South Africa
A new multidimensional fractionation technique, temperature rising elution fractionation (TREF) combined with high temperature size exclusion chromatography FTIR (HT-SEC-FTIR), HT-SEC-DSC and high temperature two-dimensional liquid chromatography (HT-2D-LC) is used for the comprehensive analysis of a commercial impact polypropylene copolymer. HT-SEC-FTIR provides information regarding the chemical composition and crystallinity as a function of molar mass. Thermal analysis of selected SEC fractions yields the melting and crystallization behavior of these fractions which is related to the chemical heterogeneity of this complex copolymer. The thermal analysis of the fractions is conducted using a novel DSC method - high speed or high performance differential scanning calorimetry (HPer DSC) - that allows measuring of minute amounts of material down to micrograms. The most interesting and complex "midelution temperature" TREF fraction (80 °C) of this copolymer is a complex mixture of ethylene-propylene copolymers (EPC's) with varying ethylene and propylene contents and sequence length distributions, as well as iPP. High temperature solvent gradient HPLC has been used to show that there is a significant amount of PE homopolymer and EPC's containing long ethylene sequences in this TREF fraction. High temperature 2D-LC analysis reveals the complete separation of this TREF fraction according to the chemical composition of each component along with their molar mass distributions. © 2012 American Chemical Society.
Chemical compositions; Chemical heterogeneities; Complex compositions; Complex mixture; Comprehensive analysis; Crystallinities; Ethylene propylene copolymers; FTIR; High temperature; Impact polypropylene copolymer; Melting and crystallization; Molar mass distribution; Multidimensional analysis; Sequence length distributions; Solvent gradients; Temperature-rising elution; Two-dimensional liquid chromatography; Copolymers; Differential scanning calorimetry; Ethylene; Liquid chromatography; Propylene; Thermoanalysis; Thermoplastics; Polypropylenes