Researchers Uncover How Everyday Plastics Break Down into Harmful Nanoparticles
A new study led by chemical engineers at Columbia University reveals the molecular mechanism responsible for the widespread formation of nanoplastics from semicrystalline polymers — the most common class of plastics used in industry today. The findings have implications for polymer design and durability, particularly for sectors managing long-term environmental impact from plastic materials.
Published March 28 in Nature Communications, the research demonstrates that nanoplastics originate in the amorphous (soft) regions of plastic, which weaken over time due to environmental degradation — even in the absence of mechanical stress. Once these soft layers fail, they allow crystalline (hard) fragments to detach and disperse. These crystalline shards are responsible for the persistent micro- and nanoplastics found in natural ecosystems and human bodies.
“Seventy-five percent of all plastics used have a layered brick-and-mortar structure,” explained Sanat Kumar, a chemical engineering professor at Columbia and the study’s lead author. “We show how easily those soft connectors break even under quiescent conditions such as in a landfill. Once that layer fails, the hard segments have nowhere to go — they scatter into the environment,” he shared in a press statement.
Lab simulations confirmed that the soft layers deteriorate over time and facilitate the release of hard crystalline particles. These nanoplastics, similar in shape and size to asbestos fibers, have been shown to pass through cellular membranes and potentially disrupt DNA — raising concerns about long-term human health effects such as cancer or cardiovascular disease.
The researchers said the next step is to explore architectural modifications to the soft-phase design in polymers. By enhancing the resilience of these amorphous layers, the release of crystalline nanoplastics could be minimized. This work points to a potential engineering solution that balances mechanical performance with environmental safety.
Kumar noted that focus needs to be placed on the structural stability of these soft regions, adding that they could be a key to reducing nanoplastic formation during normal degradation.
According to the researchers, the study also raises broader questions about the cost-benefit of plastic recycling. With only 2% of plastic currently recycled, the long-term health implications of nanoplastics may present a stronger economic case for investing in more robust recycling systems, Kumar noted.
