Plastic waste, especially small products like bread clips, presents a significant environmental challenge due to difficulties in recycling and collection. To address this, a fully biodegradable composite material was developed using pineapple field waste. Waste pineapple stem starch, rich in amylose content, served as the matrix, while glycerol and calcium carbonate were added as plasticizer and filler, respectively, to enhance moldability and hardness. Varying the amounts of glycerol (20-50% by weight) and calcium carbonate (0-30 wt.%) resulted in composite samples with a wide range of mechanical properties. The materials exhibited tensile moduli ranging from 45 to 1100 MPa, tensile strengths of 2-17 MPa, and elongation at break of 10-50%. They displayed good water resistance and lower water absorption (about 30-60%) compared to other starch-based materials. In soil burial tests, the material completely disintegrated into particles smaller than 1 mm within 14 days. A prototype of a bread clip was created to test the material’s ability to securely hold a filled bag. These findings highlight the potential of using pineapple stem starch as a sustainable alternative to petroleum-based and biobased synthetic materials for small-sized plastic products, contributing to a circular bioeconomy and reducing environmental impact.
Reference: “Toward a Circular Bioeconomy: Development of Pineapple Stem Starch Composite as a Plastic-Sheet Substitute for Single-Use Applications”, Thongphang, C., Namphonsane, A., Thanawan, S., Chia, C.H., Wongsagonsup, R., Smith, S.M., Amornsakchai, T., Polymers, 2023, 15(10), 2388.