Japan: Scientists develop self-healing, stronger and partially biodegradable plastic

Scientists in Japan have developed a new version of plastic which is not just stronger and stretchier than the traditional version but also partially biodegradable. Besides, it can remember complex shapes which can be restored once it is heated.

Sustainable plastics

Scientists worldwide for long have been pursuing the goal of creating an eco-friendly alternative to traditional plastic due to its devastating impact on the environment.

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Now, researchers at the University of Tokyo have successfully created “sustainable plastic,” which is based on an epoxy resin vitrimer.

What are vitrimers?

Vitrimers represent a relatively recent category of plastics known for their impressive strength at low temperatures, while also possessing the unique ability to be reshaped numerous times when exposed to higher temperatures.

Nonetheless, they do have a notable drawback - extreme brittleness, as they cannot be stretched far before breaking.

To address this issue, researchers introduced a molecule called polyrotaxane into the plastic synthesis process, resulting in a novel plastic variant they've dubbed VPR, an abbreviation for "vitrimer incorporated with polyrotaxane."

At lower temperatures, VPR's robust internal chemical bonds maintain its rigid shape, but as temperatures rise, to around 150 degrees Celsius, these bonds start to recombine, allowing the material to take on different forms.

Moreover, when heat and a solvent are applied to VPR, it readily breaks down into its constituent components. Submerging VPR in seawater for 30 days also led to a 25 per cent biodegradation, with the polyrotaxane breaking down into a potential food source for marine life.

Self-healing properties

“VPR is over five times as resistant to breaking as a typical epoxy resin vitrimer,” said Professor Shota Ando, a project research associate at the University of Tokyo Graduate School of Frontier Sciences.

“It also repairs itself 15 times as fast, can recover its original memorised shape twice as fast and can be chemically recycled 10 times as fast as the typical vitrimer. It even biodegrades safely in a marine environment, which is new for this material,” Ando added.

(With inputs from agencies)