The accumulation of plastic waste in the ocean poses a significant threat to the environment and human health. In response, 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 overcomes the limitations of traditional starch-based bioplastics.
The team addressed issues such as brittleness, hydrophilicity, and thermal properties by constructing a covalent adaptable network in the starch plastic. This network weakens the hydrogen bonding between starch molecular chains, giving the plastic superior flexibility, waterproof capability, excellent thermal processability, and self-adaptability.
The production process involved subjecting dialdehyde starch to a mild Schiff base reaction with a plant oil-based diamine. This formed dynamic imine bonds that could be cleaved and reformed reversibly under heat stimulation, resulting in a starch plastic with remarkable thermal processability. The presence of long aliphatic chains in the diamine enhanced the steric hindrance of the starch molecule chains, improving flexibility and hydrophobicity.
The transparent starch plastic also demonstrated self-healing capability. It could repair both scratches and large-area damage with a simple heat-pressing treatment, achieving a self-healing efficiency of over 88% in terms of mechanical properties.
This innovative design strategy opens up possibilities for sustainable, thermal processable, and degradable bioplastics using fully bio-based materials. It offers potential applications in various industries.
Sources:
– 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
