Advanced Characterization and High-Temperature Separation of Polyolefins

Created by potrace 1.16, written by Peter Selinger 2001-2019

The most widely and commercially important polymers are polyolefins. Serving in important day-to-day functions, this class of materials continues to grow yearly. Our polyolefin team is one of a handful worldwide dedicated to the unravelling polyolefin microstructure and improving existing analytical techniques. Whether you are developing a new product, synthetic pathways, trying new catalysts or recycling existing materials, we are your knowledge partner. In addition, we possess the necessary experience and a motivated research team to develop methods that can be adapted to sample needs.


HT Lab Team

Robert Kwinda

MSc Student

Dr. martin Geisler

Postdoctral fellow

Petronella Ndlovu

PhD candidate

Thandekile Siwela

MSc Student

Mawande Sigwinta

PhD candidate


HITT- High Temperature Thermal Field Flow Fractionation

Meeting the Challenges in Advanced Characterization of Branching and Ultra-High Molar Mass Distributions in Polyolefins.

2021 – 2024

NRF Postgraduate Scholarship

Advanced Separation and Characterization of Chain Walking Polyethylene.

2021 – 2023

DFG project LE 1424/7-1 BRACAT

Branching design in polyolefins by catalyst variation. Theory meets experiment.

2015 – 2020

Sasol Project

Structure-property correlations in recycled polyolefins.

2023 – 2024

Application of HT Techniques

Molar mass Separation

State-of-the-art high-temperature size exclusion chromatograph (HT-SEC) equipped with refractive index/ultraviolet/infrared (RI, UV, IR respectively) detection systems as well as multiangle laser light scattering (MALLS) and viscometry detectors.

Chemical Composition Separation

Our group is part of a handful worldwide and the only one in Africa capable of performing advanced chemical composition separations of polyolefins with techniques such as crystallization analysis fractionation (CRYSTAF), crystallization elution fractionation (CEF), temperature rising elution fractionation (TREF), and interaction chromatography (IC).

Hyphenated techniques

For detailed structural elucidation of new and existing polyolefin materials, coupling to information-rich detectors or further separation techniques is required. Chromatographic techniques can be hyphenated online or offline to infrared spectroscopy. The LC-transform interface is one of our reliable instruments for offline coupling of chromatographic separation techniques to infrared (IR), atomic force microscopy (AFM) and differential scanning calorimetry (DSC). IC can be reliably coupled to fast SEC in comprehensive high temperature two-dimensional liquid chromatography (HT-2D-LC) to relate chemical composition and molar mass parameters.

Preparative fractionation

Our group is renowned worldwide for polyolefin fractionation using preparative techniques such as temperature rising elution fractionation (p-TREF), solution crystallization fractionation (p-SCF) and molar mass fractionation (p-MMF). We also possess the flexibility to deal with difficult samples which are in product development. Most equipment can be quickly built inhouse and used efficiently for fractionation.


All publications of the HT lab team can be viewed here.

Past and present Collaborators