High Temperature Thermal Gradient Interaction Chromatography (HT‐TGIC) for Microstructure Analysis of Polyolefins

Abstract

Summary: High temperature thermal gradient interaction chromatography (HT‐TGIC) is a newly developed technique to analyze comonomer distributions in polyolefins. This paper documents the key differences between crystallization elution fractionation (CEF) and HT‐TGIC, and the advantages of using multiple detectors in HT‐TGIC to provide comprehensive microstructure characterization. A demonstration of the technique using a specifically designed blend, provides comprehensive data in less than 1.5 hours of analysis time by HT‐TGIC. This paper also reports that HT‐TGIC has excellent short term repeatability.

Separation of Polypropylene Polymers by Crystallization and Adsorption Techniques

“…The separation of most olefin copolymers by TGIC follows the expected straight‐line correlation between desorption temperatures and comonomer content; an increasing presence of side‐chain branches with more comonomer incorporation reduces the molecule surface of interaction with the ALFS adsorbent and it desorbs/elutes at lower temperatures. We should expect this behavior with all ethylene copolymers, however, due to the crystallization of the semicrystalline PP in TGIC before adsorption, it is not a surprise that a U‐shaped curve is obtained with EP copolymers of different comonomer incorporation, as it is shown in Figure a, which resembles the TREF and CRYSTAF curves of Figure .…”

High Temperature Thermal Gradient Interaction Chromatography (HT‐TGIC) for Blends of Ethylene/1‐Octene Copolymers: A Mathematical Model

“…Recently, high temperature thermal gradient interaction chromatography (HT‐TGIC) was developed to determine CCD based on the interaction between polymer chains and graphitic surface. HT‐TGIC was found to provide fast CCD characterization over much wider range of comonomer contents ( cc ) compared to other crystallization‐based techniques …”

Advances in Thermal Gradient Interaction Chromatography and Crystallization Techniques for Composition Analysis in Polyolefins

“…A Temperature Gradient Chromatographic approach has been shown to be an alternative to solvent gradient in the separation of polymers as shown by Chang who has reported separation of polystyrene and other polymers by molar mass when using a reverse phase column. A significant breakthrough came with the use of the temperature gradient approach but on graphitized carbon instead of a reverse phase column to separate polyethylene copolymers, as shown by Cong et al; the new approach has become known as Thermal Gradient Interaction Chromatography (TGIC).…”