Recently, researchers at the University of Tokyo's (UT) Graduate School of Frontier Sciences have developed innovative plastics that are stronger and more resilient than current standard plastics, are partially biodegradable, and have shape-memory capabilities that can be restored once heated.
The researchers created the material by adding polyrotaxane (PR) molecules to epoxy resin vitrimer, a type of plastic. They named it VPR, an acronym for vitrimer incorporated with polyrotaxane.
At lower temperatures, VPR's strong internal chemical bonds maintain their rigid shape, but as the temperature rises, to about 150 degrees Celsius, these bonds begin to reorganize, giving the material a different form.
Prof. Shota Ando, an associate researcher on the project, said the VPR is more than five times more resistant to fracture than a typical epoxy glass. It repairs itself 15 times faster than a typical epoxy glass mirror, recovers its memorized shape twice as fast, and chemically recycles 10 times faster than a typical epoxy glass mirror.
In addition, when heat and solvents are applied to VPR, it readily breaks down into its constituent parts. Submerging VPR in seawater for 30 days also resulted in 25% biodegradation, with polyrotaxanes breaking down into a potential food source for marine organisms.
