Plant plastics reach for the stars

Researchers in Finland have transformed rice starch into a temporally stable, optically transparent, biodegradable plastic with a high degree of mechanical strength and good thermal resistance. This important step towards bioplastics made from simple and sustainable resources has potential applications in food packaging and biomedical materials.

A brittle polymer, starch can be treated with heat and water, via a technique called gelatisation, to make it suitable for traditional plastic processing techniques. However, films prepared by this method rapidly recrystalise and degrade, leaving them amorphous and brittle again. Many small molecules have been used as plasticisers that hydrogen bond with the glucose units in starch to prevent recrystallisation, however they are prone to migration and leeching, again degrading over time. Unfortunately larger compounds are typically less effective plasticisers.

Virginia Nykänen and colleagues at Aalto University have devised a creative solution to this problem.

This article provides a link to coverage by Chemistry World