Development of biodegradable bag materials as a sustainable alternative to conventional plastic bags

Biodegradable plastics are actively studied to address the environmental issues caused by petroleum-based plastics. Sodium-alginate-based biodegradable materials containing crosslinking agents and stearic acid have been developed. A sodium alginate-based bag was fabricated by immersing a film composed of sodium alginate and stearic acid into a calcium lactic acid solution, to induce transformation through calcium bonding. These bags exhibited variations in tensile strength (TS), breaking height (E), moisture absorption, swelling, and contact angle depending on the percentage of stearic acid (1, 3, 5, 8, and 10 %); additionally, stearic acid showed a rough surface in morphological measurements. The rough surface facilitated effective integration with stearic acid, ultimately improving hydrophobicity. This was confirmed by a water absorption experiment. In addition, the combination of stearic acid and sodium alginate resulted in an increased breaking height, demonstrating comparable performance to conventional plastic bag. The interaction between sodium alginate and stearic acid shows that the generated biodegradable bags exhibit physical properties similar to those of the conventional plastic bags.