The accumulation of plastic waste in our oceans poses a significant threat to the environment and human health. In an effort to address this issue, researchers from the State Key Laboratory of Pulp and Paper Engineering at South China University of Technology have developed a novel strategy for creating a fully bio-based starch plastic that exhibits superior properties such as flexibility, waterproof capability, thermal processability, and self-healing ability.
Starch is an ideal material for bioplastics due to its abundance and renewable nature. However, it has certain limitations that make it unsuitable for widespread application, such as brittleness, hydrophilicity, and thermal properties. To overcome these challenges, the researchers constructed a covalent adaptable network that weakened the hydrogen bonding between starch chains and improved stress relaxation.
The production of the fully bio-based starch plastic involved a reaction between dialdehyde starch and a plant oil-based diamine, resulting in the formation of dynamic imine bonds. These bonds can be cleaved and reformed reversibly under heat stimulation, giving the plastic remarkable thermal processability. The presence of long aliphatic chains in the diamine also enhanced the flexibility and hydrophobicity of the starch plastic.
One of the notable features of the transparent starch plastic is its self-healing capability. It can repair both scratches and large-area damage through a simple heat-pressing treatment, with a self-healing efficiency of over 88% in terms of mechanical properties.
The development of this innovative design strategy opens up new possibilities for sustainable, thermal processable, and degradable bioplastics made from fully bio-based materials. This research contributes to the ongoing efforts to reduce plastic waste and protect our environment.
Source: Xiaoqian Zhang et al, Flexible, thermal processable, self-healing, and fully bio-based starch plastics by constructing dynamic imine network, Green Energy & Environment (2023). DOI: 10.1016/j.gee.2023.08.002
Source: KeAi Communications Co. (Phys.org)