Effect of chitosan concentration on physicochemical properties of starch-based straws

China’s 2021 ban on disposable (single-use) plastic straws and bags has necessitated the invention of more biodegradable straws. However, the application of starch-based straws is limited by their poor mechanical properties. Under high-temperature and high-pressure conditions, starch becomes a paste and its molecular hydrogen bonds are broken. After adding chitosan (CH), the CH and starch can form new hydrogen bonds. Biodegradable starch-based straws were made from cassava starch and rice starch (weight ratio = 1:1; CR) by using the extrusion technique. CH (0, 5, 10, 15 and 20%) was added to improve the mechanical properties of the straws, and the effect of CH on the chemical, mechanical and water resistance properties of the starch-based straws was investigated. The color, transparency and water resistance of CR/CH straws containing different levels of CH were superior to those of CR straws. The best mechanical properties and water resistance of starch-based straws were obtained when the CH addition was 5%. The addition of CH flattened the appearance of the starch-based straws and improved the mechanical properties and water resistance of the straws. The aforementioned structure can provide a reference for the application of starch-based materials.