Work

Biodegradable composite films from carrageenan, chitosan, and modified starch with enhanced mechanical strength and barrier properties for sustainable packaging

Year: 2026

Type: article

Abstract: The development of biodegradable packaging materials from renewable biopolymers is increasingly important for reducing dependence on petroleum-derived plastics. This study investigated the design and characterization of composite bioplastic films based on carrageenan (CG), chitosan (CS), and modified starch (MS) as a sustainable polysaccharide matrix. Films were prepared using a solution-casting method by blending Kappaphycus alvarezii -derived carrageenan (0.5% w/v) with varying CS-MS ratios (1% w/v total solids) and glycerol (40% w/w of total solids) as a plasticizer. The CS-MS composition significantly influenced film performance, demonstrating the importance of polymer interactions within the ternary matrix. Optical properties varied among formulations, with MS100 (0% CS:100% MS) exhibiting the highest opacity (5 ± 0.6 mm − 1 ). The CS80 formulation (80% CS:20% MS) showed the highest tensile strength (12.71 ± 0.08 MPa), whereas MS100 presented the greatest elongation at break (22.6 ± 1.9%), indicating improved flexibility. Water vapor permeability was lowest in CS60 (1.3 ± 0.10 × 10 − 10 g m − 1 s − 1 Pa − 1 ) and CS40 (1.4 ± 0.12 × 10 − 10 g m − 1 s − 1 Pa − 1 ), suggesting enhanced moisture barrier performance. Thermal stability ranged from 303 to 325 °C, indicating resistance to thermal processing conditions relevant to food packaging. Biodegradation tests revealed rapid physical disintegration under modified compost conditions, with CS20 and MS100 films achieving complete mass loss within 7 days, while CS100 exhibited 42 ± 4% mass loss. Overall, the results demonstrate that integrating carrageenan with chitosan and modified starch produces a ternary polysaccharide matrix with improved mechanical strength, barrier properties, and biodegradability relative to most reported single-polysaccharide films. These findings provide insight into the design of multi-polysaccharide biodegradable films and highlight their potential as candidate materials for sustainable food packaging applications within a circular bioeconomy framework.

Source: Discover Sustainability

DOI: 10.1007/s43621-026-04312-4