Researchers in Japan have developed a new type of bio-based plastic that outperforms polyethylene and polypropylene, two of the most widely used plastics in the world, in terms of tensile strength and elasticity. The material is made from non-edible plant oils, amino acids, and sugars, and is also chemically recyclable. The findings have been published in the scientific journal JACS Au.
The research was conducted by the research group of Professor Kotohiro Nomura of Tokyo Metropolitan University, in collaboration with the Osaka Research Institute of Industrial Science and Technology and the University of Shiga Prefecture. The group developed so-called biobased poly(ester amide)s: polymers that contain both ester groups and amide groups and are composed of renewable, non-food-competing raw materials.
Stronger than conventional plastics, yet recoverable
Producing bio-based plastics that are both highly chemically recyclable and mechanically competitive with existing commodity plastics proves difficult in practice. Materials that can easily be broken down into their building blocks typically have lower tensile strength than polyethylene or polypropylene. The Japanese team circumvented this problem with a polymerization method based on catalytic olefin metathesis, which yields high molecular weight polymers. In film form, these materials have been shown to surpass both the tensile strength and the elongation at break of PE and PP films.
In addition, the chemical structure makes the material biodegradable back into its original building blocks. Through transesterification, a reaction with alcohol, the polymers decompose into the monomers of which they are composed. This enables a form of chemical recycling that goes beyond conventional mechanical recycling, where the quality of the material typically deteriorates.
A notable variant of the polymer incorporates the amino acid phenylalanine. This type exhibits rapid self-healing capabilities at room temperature: damage to the material repairs itself without the need for heat or additional treatment.
Early stage, but relevant for circular ambitions
The researchers place the work within the broader search for biobased polymers that can actually compete with fossil plastics, not only on sustainability but also on mechanical properties. Commodity plastics such as PE and PP are widespread partly because they are cheap and strong. A biobased alternative that equals or surpasses both criteria, and that is also chemically recyclable, aligns with the objectives of a circular plastics chain.
The research is currently in an early scientific stage. No information is available regarding scaling up, production costs, or potential industrial application in the short term. However, the publication adds a concrete data point to the growing body of studies showing that biobased polymers do not necessarily have to be inferior to their fossil counterparts mechanically.
Work is also being done in the Netherlands and Europe on biobased polymers that are intended to be chemically recyclable in the long term. Chemical company Avantium is developing a plant-based alternative to PET using FDCA and PEF, and Corbion is further expanding its position in lactic acid and polylactic acid (PLA). Japanese research shows that the mechanical gap between biobased plastics and fossil variants such as PE and PP is narrowing, a development that is also relevant for these Dutch players in the further scaling up of their own technologies.
Source: Phys.org
Photo: Сергей Шиманович, Adobe Stock
