TPU is a bendy plastic used in real-life products such as shoe soles, hoses, and cable coatings, because it can stay flexible while still taking wear and tear.
In a 2024 study, researchers tested if adding multi-walled carbon nanotubes, tiny carbon “tubes,” could help thin TPU films stay stable with heat, feel stronger, and carry electricity.
Meet TPU
TPU sits between rubber and hard plastic; it can stretch and bounce back, but it can also be reheated and reshaped in manufacturing.
That’s great for factories, but it comes with a common headache: When temperatures rise, many plastics start changing how they behave, sometimes getting too soft for demanding parts.
So researchers often “upgrade” a plastic by mixing in a second ingredient that acts like internal support, as long as that ingredient spreads evenly instead of forming clumps.
The tiny add-on
Carbon nanotubes are attractive fillers because they can conduct electricity and help reinforce plastics, even when added in small amounts.
The team made TPU films with 1%, 3%, 5%, and 7% nanotubes by weight, then formed thin sheets using a hot press at about 200 degrees Celsius.
The goal was a smooth film where nanotubes were spread through the material, since good dispersion helps both strength and electrical flow.
What the tests found
To keep the checks practical, the researchers looked at three big questions: How the film reacted to heat, how it resisted bending and stretching, and how well it carried charge.
On the heat side, the study reported that the temperature at which TPU’s motion “loosens up” shifted toward higher temperatures as nanotube content rose.
In everyday terms, that usually points to a film that keeps its shape and feels a bit better as things warm up, instead of turning overly soft too soon.
The study also reported the melting temperature decreasing, a clue that the inside arrangement of TPU changed once nanotubes were in the mix.
For strength, the lab stiffness measure went up with more nanotubes, and the paper reported an overall storage modulus increase of about 58.3%.
A simple picture helps. Adding nanotubes is like placing thin support sticks inside a gummy material; the film can still flex, but it resists deformation to a greater extent.
How electricity started flowing
Plain TPU is usually a poor conductor, meaning it does not like letting electricity move through it.
When enough nanotubes are added, they begin to form connected paths, like stepping stones, finally linking into a full walkway, and charge can travel across the network.
Before those paths fully connect, electrons can sometimes cross tiny gaps by “tunneling,” which works only when nanotubes sit extremely close together.
In the TPU film study, both percolation (connected paths) and tunneling showed up in the modeling for several samples.
At 7%, the film reached about 0.16 S/cm, and tunneling was hard to observe because the connected network carried charge so well.
Why this matters in Colombia
Since TPU already appears in common products such as shoe soles and cable coatings, improved TPU films could fit into familiar manufacturing routes instead of requiring brand-new materials.
If films can stay flexible while also handling more heat and carrying charge, they could support things such as anti-static packaging, simple flexible connectors, or wearable parts that need bending without breaking.
Where this research could lead
The 2024 research found a clear trend: As nanotube content increased, TPU films showed higher stiffness, shifted heat-related behavior, and much higher electrical conductivity, with the top sample reaching about 0.16 S/cm.
For nonexperts, the takeaway is straightforward: Tiny conductive tubes acted like hidden reinforcements and wiring inside a familiar plastic, turning an everyday material into something closer to “smart” flexible film.