Plastic waste pollution and its impact on the environment and human health have become significant concerns. In response, there is increasing interest in the development of renewable and eco-friendly materials. Starch, being abundant and renewable, is an attractive option for bioplastics production. However, its inherent brittleness, hydrophilicity, and thermal limitations have hindered its widespread application.
To address these challenges, a group of researchers from the State Key Laboratory of Pulp and Paper Engineering at South China University of Technology has presented a novel strategy for creating a fully bio-based starch plastic with enhanced properties. The researchers focused on improving flexibility, waterproof capability, thermal processability, and self-adaptability.
The key to enhancing the properties of starch plastic lies in weakening the hydrogen bonding between its molecular chains. The researchers achieved this by constructing a covalent adaptable network through a Schiff base reaction between dialdehyde starch and a plant oil-based diamine. This reaction formed dynamic imine bonds that could be cleaved and reformed reversibly under heat stimulation, resulting in remarkable thermal processability.
Furthermore, the inclusion of long aliphatic chains in the diamine improved the flexibility and hydrophobicity of the starch plastic by increasing the steric hindrance of the starch molecule chains. The resulting starch plastic exhibited superior flexibility, waterproof capability, and self-healing properties. Most notably, the self-healing efficiency reached more than 88% in terms of mechanical properties, allowing for the repair of both scratches and large-area damage through a simple heat-pressing treatment.
This innovative design strategy offers promising applications for sustainable and degradable bioplastics. By utilizing fully bio-based materials, the researchers have made significant progress towards the development of renewable, low-cost, and eco-friendly alternatives to traditional plastics.
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).
Citation: A thermal processable, self-healing, and fully bio-based starch plastic (2023, September 18) retrieved 18 September 2023 from https://phys.org/news/2023-09-thermal-self-healing-fully-bio-based-starch.html