A University of Tokyo study has explored the potential of a moldable plastic that is self-repairing and degrades in nature.
Scientists at the Japanese university have developed a polymer that can be easily broken down into its monomers but remains stable at room temperature. Such plastic, which is biodegradable in the ocean, turns into nutrients for the underwater ecosystem.
What do we mean by plastic?
Japanese researchers have studied a vitrimer of epoxy resin combined with a polyrotaxane molecule.
Let us try to analyze the technicalities just mentioned in order to understand, in a rather simple way, the sense and the innovative scope of the research.
- Vitrimers are a class of plastics similar to thermosetting polymers, which harden after an initial softening phase due to heating. Vitrimers can change the topology of their molecular networks by thermally activated bond exchange reactions.
- Epoxy resin is a cold-reacting thermosetting polymer consisting of a base resin and a curing agent, the mixture of which produces a glossy vitreous layer.
- Polyrotaxane, on the other hand, is a type of molecule that helps form functional molecular machines with a complex structure.
The properties of the polymer
The sum of these elements results in a new plastic called VPR that can repair a scalpel cut in just 60 seconds when heated to 150°C. That’s 15 times faster than competing materials.
The self-repairing property is complemented by the modeling one: again thanks to heating, VPR can recover its original shape after being compressed, ten times faster than traditional vitrimers.
Another striking feature of VPR plastic is its recyclability. In fact, the heat input is sufficient to break the molecular bonds. And its eventual dispersion into the environment is not harmful compared to other plastics. Immersed in seawater for only 30 days, the polymer biodegrades to 25 percent of its mass, releasing molecules that are edible for marine wildlife.
What are the potential applications?
Researchers at the University of Tokyo see numerous applications for the new polymer, which is poised to replace more polluting plastics. In particular, VPR plastic could prove strategic as an infrastructure material for roads and bridges because of its self-repairing properties.
The automotive industry is also monitoring the benefits of this new plastic, not wanting to lose out on an innovation that could be a game-changer for the sector in terms of sustainability and mechanical properties.
Source: rinnovabili.it, wikipedia.org