Scientists enhance bioplastics process

A group of scientists from the Italian Institute of Technology (IIT) has discovered a new method which can turn food waste into biodegradable plastics, using less energy than current techniques.

The research has been published in the journal Macromolecules.

Currently, bioplastics are created by processing waste plant material to create monomers, which link up to create long polymer molecules that make up plastics.

Through this method, biodegradable plastics are developed, but the multiple stages involved in its production, particularly the energy-intensive nature of the process, have been scrutinised by some experts.

Lead researchers Ilker Bayer suggests that current bioplastics processes also use crops which could otherwise be used for food.

To perfect the new method, Bayer and his team were looking at the process for creating cellophane, which involves passing cellulose, the material that makes up plant cell walls, through multiple acid and alkali baths.

According to research, the team discovered that dissolving cellulose from cotton and hemp in trifluoroacetic acid, converted it directly from its crystalline form to an amorphous form suitable for moulding into plastic without the need for any further processing.

After its initial success, the IIT team tried the process on vegetable waste products, including rice hulls, cocoa pod husks and spinach and parsley stems.

“These are the parts we don’t want to eat. They could all be easily converted into useful bioplastics, with different properties based on the starting material: rubbery for spinach, but firmer for rice hulls,” said Bayer.

Ilker said that the new materials differ in stiffness and stretchiness when compared to existing bioplastics and traditional plastics.

He also suggests the new materials inherit the properties the plant used - therefore, parsley plastic could have antioxidant properties, or cinnamon plastic could be antibacterial.