Scientists at ETH Zurich have developed an innovative recycling technique that transforms discarded plastic bags and bottles into high performance industrial adhesives. The breakthrough could offer a promising solution to the growing global plastic waste crisis while creating valuable new materials from commonly discarded plastics.
The new one step chemical process converts polyethylene (PE) and polypropylene (PP), two of the world’s most widely used plastics, into advanced adhesive materials. Unlike conventional recycling methods, which often reduce plastic quality, the technique preserves the original polymer structure while introducing new chemical properties.
The research team, led by Tae Lim Choi, professor of polymer chemistry at ETH Zurich, demonstrated that the modified materials can produce strong adhesives capable of bonding metals, glass and wood. These adhesives could potentially be used in demanding applications, including vehicle and equipment manufacturing.
Polyethylene and polypropylene account for approximately half of global plastic consumption. Around 450 million metric tons of plastic are produced worldwide every year, with a significant proportion eventually ending up in landfills or incinerators.
Traditional mechanical recycling involves melting and reshaping plastic waste, often resulting in weaker or lower quality materials. These recycled plastics are frequently used in products such as paving slabs and plant pots.
The new technology takes a different approach by modifying existing plastic polymers rather than breaking them down into smaller chemical components.
Researchers attach new polymer chains to the original plastic structure, introducing properties that conventional plastics do not naturally possess.
How Light Based Chemical Recycling Works
The technique begins by dissolving discarded plastic in a chlorinated solvent. Researchers then expose the solution to short wavelength light, which generates highly reactive chlorine radicals.
These radicals activate carbon atoms along the plastic polymer chains without destroying the original structure. The activated locations act as attachment points where new polymer chains can grow.
Through this process, scientists can modify the chemical characteristics of plastic in a single reaction.
The method does not require expensive catalysts or extremely high processing temperatures, potentially making it simpler than several advanced chemical recycling technologies currently being developed.
Researchers can also control the reaction by adjusting the solvent’s degree of chlorination and the wavelength of the light, allowing them to influence how many new chemical attachment points are created.
Technology Could Transform Packaging and Industrial Manufacturing
Beyond producing industrial strength adhesives, the technology could support the development of plastics with entirely new properties.
By attaching different polymer chains, researchers can introduce water-attracting groups, acids, bases and other specialised chemical functionalities.
One potential application involves food packaging. ETH Zurich researchers are collaborating with industry partners to explore modified polyolefin materials that maintain waterproof properties while providing improved oxygen barriers.
Such packaging could help reduce food oxidation and freezer burn, potentially extending product quality and shelf life.
The technology could also contribute to improving the quality of recycled plastics. According to senior scientist Hongsik Kim, the newly developed adhesive could act as a binding material that strengthens low-grade recycled plastics, helping transform them into more durable and valuable products.
ETH Zurich has patented the innovative recycling technique and nominated it for the university’s Spark Award, which recognises promising technological inventions.
Following the publication of the patent, researchers have started working with industry partners to explore potential commercial applications.
Professor Tae Lim Choi described the adhesive as a first generation product, suggesting that further developments could make it possible to manufacture plastics with entirely new characteristics.
The research represents a promising step towards more advanced plastic recycling. If successfully scaled up for industrial production, the technology could help reduce plastic waste, improve the value of recycled materials and create new opportunities for sustainable manufacturing.