Reviewed by Lexie CornerDec 17 2024
A strong and impact-resistant plastic, comparable to steel, could soon be processed more efficiently, thanks to new strategies developed and tested by researchers in England. Their findings were published in the journal Industrial Chemistry & Materials.
Four strategies to enhance the processability of UHMWPE are explored using heterogenized metallocene catalysts to produce polymers with decreased melt viscosity and excellent mechanical performance. Image Credit: Dermot O'Hare, University of Oxford Department of Chemistry, UK
The researchers explored four techniques to enhance the melt processability of ultra-high molecular weight polyethylene (UHMWPE), which involves melting the material and reshaping it into a solid structure. Melt processability can be challenging when the material has high melt viscosity, meaning the liquid resists flow, as explained by Dermot O'Hare, a chemistry professor at the University of Oxford and corresponding author of the study.
UHMWPE, defined by a molecular weight in the millions of Daltons that indicates the molecule’s large size and complex nature, is a specialty grade of polyethylene considered an important engineering plastic due to its desirable properties. However, due to the long chains comprising the molecule creating entanglements, UHMWPE can be difficult to process. We investigated four strategies to improve UHMWPE melt processability, which is the chief limiting factor to applications of this high-performance polymer.
Dermot O’Hare, Study Corresponding Author and Professor, University of Oxford
The team initially experimented with active site engineering, which speeds up and improves material reactions. They found that this method significantly helped untangle large, complex molecules. They then used chain transfer agents, or molecular modifiers, to adjust the weight and distribution of the polyethylene.
Additionally, they discovered that incorporating small molecules into UHMWPE improved its processability while preserving its mechanical properties. The researchers also found that blending UHMWPE with high-density polyethylene further enhanced processability.
“These approaches and combinations thereof are considered crucial to expanding the applicability of UHMWPE,” O’Hare added.
The team also plans further research into how combining different processing techniques could lead to the development of materials with new and unique properties.
Clement G. Collins Rice, Alexander Evans and Zoë R. Turner, Chemistry Research Laboratory in the University of Oxford Department of Chemistry; and Jirut Wattoom, SENFI UK Ltd., Centre of Innovation and Enterprise, Begbroke Science Park, and SCG Chemicals PLC are the other study co-authors. Collins Rice is also affiliated with SENFI UK Ltd., Centre of Innovation and Enterprise, and Begbroke Science Park.
The study was funded by SCG Chemicals PLC and the Engineering and Physical Sciences Research Council Impact Acceleration Account.
Journal Reference:
Rice, C. G. C., et. al. (2024) Strategies for enhancing the processability of UHMWPE. Industrial Chemistry & Materials. doi.org/10.1039/D4IM00104D