Scientists in the United States have developed a promising technology that could significantly improve the recycling of two of the world’s most widely used plastics – polyethylene (PE) and polypropylene (PP).
Researchers at the University at Buffalo introduced a solvent-based recycling method aimed at solving one of the biggest challenges in plastic waste management: recycling flexible plastic materials commonly used in packaging and consumer products.
Why Polyethylene and Polypropylene Are Difficult to Recycle
Polyethylene and polypropylene belong to the polyolefin family, which represents the largest portion of global plastic production. These plastics are widely used in packaging, plastic films, containers, and various household items.
However, flexible plastics and multilayer packaging materials are difficult to recycle using traditional mechanical methods. Because of this limitation, a large share of these plastics ends up in landfills or pollutes the environment.
Global plastic production reached more than 359 million tons in 2024, with polyolefins accounting for over half of that amount.
How the Solvent-Based Recycling Method Works
The research team, led by chemical engineering professor Pascal Alexandridis, is studying a solvent-based technique that dissolves plastic materials in carefully selected solvents.
Once dissolved, purified polymers can be separated from additives, contaminants, and other materials. Unlike high-temperature recycling methods such as pyrolysis, this process preserves the structure of polymer chains.
As a result, the recovered plastics can be reused to manufacture new products without significant loss in quality.
Studying Polymer Behavior at the Molecular Level
To better understand how plastics dissolve during the process, the scientists conducted detailed laboratory experiments combined with computer simulations.
The research revealed that polypropylene granules first lose their crystalline structure before they begin dissolving. The team also developed a predictive model to explain how solvents penetrate polyethylene at different temperatures.
Additionally, researchers designed a special experimental system that allows real-time observation of polyethylene’s structural changes using infrared spectroscopy.
Potential Impact on Global Plastic Waste
Experts believe the technology could help improve global recycling systems and reduce environmental pollution caused by plastic waste.
Currently, less than 10 percent of plastic waste worldwide is recycled, largely due to difficulties in separating complex plastic materials.
If adopted on a larger scale, the solvent-based method could allow purified polymers to be recovered and reused in manufacturing, reducing the need for new plastic production and lowering environmental impact.
Future Applications Beyond Recycling
Beyond waste management, scientists say the research could also help develop advanced polymer materials and innovative technologies.
The insights gained from this work may support new applications in areas such as material science, packaging design, and even controlled drug delivery systems.
The breakthrough highlights how advances in polymer research could play a key role in addressing the growing global plastic pollution challenge while promoting more sustainable industrial practices.