A new drive to produce degradable plastic has come from the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland.
It has developed a plastic from non-edible plant parts that disintegrates into harmless sugars In the environment.
The plastic has properties close to conventional plastics, meaning it is a promising prospect for food and beverage packaging. It is robust, resists high temperatures and blocks gases like oxygen that can be damaging for food.
The product contrasts with current commercial bioplastics, which are expensive, cannot endure high temperatures or act as an appropriate barrier to gases. They also cannot be stretched and drawn into different forms.
In 2016, the EPFL researchers discovered a way to make valuable molecules for plastics and biofuels from the woody, inedible parts of plants. The new work published in Nature Chemistry takes that project forward. This time, they used glyoxylic acid instead of formaldehyde to turn lignin into key building blocks of plastics. They were able to convert up to 25 percent of the weight of agricultural waste into plastics.
The process is simple and scalable, and uses an inexpensive mineral acid as the catalyst, according to the researchers. And glyoxylic acid is an inexpensive industrially available chemical.
Tests in the laboratory showed that the plastic can withstand temperatures as high as 100°C, and has similar strength. The team could also draw it into packaging film.
The material could be chemically recycled just like fossil-based plastics. And if it reaches the environment, it eventually degrades back into its constituent sugars in room-temperature water.
Whilst a promising prospect for sustainable plastic, the researchers said: “in-depth toxicological and biodegradation tests are still required before this polymer’s environmental fate is fully understood”.
Step forward for biomass-produced plastic
