Transforming polyethylene: from functionalization for sustainable applications to antimicrobial properties

Hydroaminoalkylation allows efficient incorporation of amine groups into polyethylene, which are subsequently converted to antimicrobial ammonium groups. Credit: Saeed Ataie
Polyethylene (PE) is one of the most widely used and versatile plastic materials around the world, valued for its cost-effectiveness, lightweight properties, and ease of molding. These properties make PE essential across a wide range of applications, from packaging materials to structural plastics.
However, despite its widespread use, PE’s inherent chemical inertness limits its functionality in advanced applications and hinders its potential for more innovative applications.
To unlock this potential, it is essential to introduce polar functional groups into PE. This significantly enhances the properties of PE and opens the door to new applications. This challenge has become a major focus in polymer chemistry, and there is growing interest in developing efficient methods to modify PE.
One of the main obstacles in modifying PE is its chemical resistance, which makes it difficult to functionalize using traditional methods. This inertness also contributes to the accumulation of PE waste in landfills, causing serious environmental problems. As plastic pollution continues to threaten ecosystems around the world, it is essential to find ways to recycle or upcycle PE into valuable products.
Although several approaches to modifying PE exist, they often lack scalability and efficiency, requiring innovative solutions that balance the environmental impact and functional benefits of this ubiquitous plastic. The need for this is emphasized.
Among the various strategies available, amination has emerged as one of the most promising ways to modify PE.
But why focus on amines?
Amines are nitrogen-based groups with one or more hydrogen atoms attached in the form of an NH bond. These NH groups participate in hydrogen bonding and allow interactions between polymer chains. This not only increases the chemical reactivity of the polymer, but also improves its performance across a variety of applications, from adhesives to coatings.
However, efficiently functionalizing PE using amines has been a major challenge. Most methods require multiple energy-intensive steps and risk degrading polymer properties.
As a result, progress toward scalable and effective methods for aminating PE has been limited. In particular, converting the NH groups of aminated PE to other species could further expand the range of applications of PE.


Thin film of polyethylene functionalized with antimicrobial ammonium groups. Credit: Saeed Ataie
This is where my research as a postdoctoral fellow in the Schaefer Group at the University of British Columbia takes a bold step forward.
Through extensive research, I focused on a catalytic process called hydroaminoalkylation that efficiently aminates PE. This technology, previously used to modify polypropylene, had the promise of converting PE in a simple, one-step reaction.
The research is published in the journal Angewandte Chemie International Edition.
The strength of this method lies in its efficiency. It works under mild, solvent-free conditions and avoids the radical-induced decomposition seen with traditional methods. By applying this approach to vinyl-terminated polyethylene (VTPE), which was generously provided by my industrial partner NOVA Chemicals, I was able to successfully create amine-functionalized PE with a minimum of reaction steps and improved performance and cost effectiveness.
At the University of British Columbia, colleagues from the Hadjikyriakos group performed rheological and mechanical testing of my aminated PE. They found that the introduction of amine groups not only changes the chemical properties of PE but also affects its physical properties.
For example, the crystallization temperature of the modified PE increased, indicating stronger intermolecular interactions within the polymer due to the amine groups. The amine groups also increased the hydrophilicity (or attraction to water) of the material, as the NH bonds could form hydrogen bonds with water molecules.
Traditionally, PE has been difficult to recycle due to its chemical inertness, but this new approach allows PE waste to be upcycled into a valuable resource. Amination of waste PE holds great promise for sustainability and allows for reuse and reuse in a variety of applications.
Now, imagine a world where you don’t have to sanitize your hands every time you touch a surface, a common concern during the COVID-19 pandemic. This is the question I aimed to address in my research.


Completely reduces Staphylococcus aureus bacteria in the presence of antibacterial polyethylene. Credit: Saeed Ataie
Here’s how amination provides antibacterial effects. By treating the aminated PE with a hydrochloric acid solution, the amine groups in the polymer were converted to positively charged ammonium groups. Bacteria have negatively charged cell membranes and are naturally attracted to positively charged ammonium groups.
This electrostatic interaction destroys the bacterial cell membrane and ultimately kills the bacteria. After this conversion, my collaborators at the University of Calgary, the Hein team, exposed the modified polymer to Staphylococcus aureus. The polymer killed all bacteria with a short exposure time.
Essentially, I developed an antimicrobial polymer that has the potential to be used as a coating on everyday surfaces, providing a way to prevent the spread of bacteria without the need for regular disinfection.
This story is part of the Science X Dialog, where researchers can report findings from published research papers. To learn more about Science X Dialog and how to participate, visit this page.
Further information: Saeed Ataie et al, Amine functionalization of vinyl-terminated polyethylene by hydroaminoalkylation provides direct access to responsive functional materials, Angewandte Chemie International Edition (2024). DOI: 10.1002/anie.202410154
I am a postdoctoral fellow in the Schaefer Group at the University of British Columbia. My research focuses on the design of catalysts for the hydroaminoalkylation of polyolefins. Before becoming a postdoc, I completed my Ph.D. in inorganic chemistry and catalysis from the Baker Group at the University of Ottawa.
Citation: Transforming Polyethylene: From Functionalization to Antimicrobial Properties for Sustainable Applications (November 9, 2024), November 9, 2024 https://phys.org/news/2024-11-polyene- Retrieved from functionalization-antibacteria-properties-sustainable.html
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