Influence of additives on the development, mechanical, functional characteristics and biodegradability of banana starch-based bio plastic films

Starch-based bio plastics, due to their abundance, recyclability, and biodegradability, offer a promising alternative to conventional petrochemical-based plastics. Additives significantly influences the functionality of bioplastics. This study investigates the effects of polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) at varying concentrations on banana starch-based bioplastic films, using glycerol as a plasticizer. CMC-based films exhibited higher L* values and thickness (0.51-1.55 mm) compared to PVA films. Due to hydrophilicity, CMC films demonstrated 2-3 times greater solubility (17-23 %) and water absorption (75.29 %). Moisture-rich films, C3 and PC2:1, showed the highest WVTR values of 25.73 and 24.10 g/m²/day, respectively, while PVA-rich films (1-1.5 %) had lower WVTR. Increasing CMC concentration reduced OTR values (2.59-3.58 cm³/m²/day) compared to PVA (4.19-5.23 cm³/m²/day). PVA enhanced transparency and smoother morphology, while CMC imparted texture and fibrous structures. Gloss values ranged from 9.82 (P1) to 40.88 (PC2:1), with CMC films exhibiting 3-4 times higher gloss. Tensile strengths varied from 8.34 MPa (C1) to 24.73 MPa (C2), highlighting CMC's mechanical enhancement, while P1 achieved the highest elongation of 90.23 %. FTIR spectra confirmed banana starch matrices, and CMC's crystalline nature at 2θ = 23° reduced polarity and crystallinity, influencing water absorption. These insights support designing banana starch-based bioplastics for a sustainable future.