Optimization, Characterization, and Moisture Sorption Isotherm Studies of Tamarind Polysaccharide/PVA‐Based Biodegradable Films

The present study details the optimization, characterization, and moisture sorption properties of films fabricated from tamarind polysaccharide (TP), PVA, and glycerol. Single‐factor experiments showed that a 5 g TP/100 mL solution is ideal for film formation. TP (5 g) and PVA (0.875 g) were blended with a composition of 85 and 15 wt.%, respectively, in 100 mL of water. Next, amounts of glycerol and glutaraldehyde were optimized using response surface methodology. Box–Behnken design was used to analyze the effects of glycerol (0.5–4.0 mL/100 mL) and glutaraldehyde (0–1.25 g/100 mL) on the film's mechanical properties, namely, tensile strength (TS) and elongation at break (% El). Glycerol played a significant role in affecting both TS and % El. The optimum conditions were found to be: glycerol 70 wt.%, glutaraldehyde 3.6 wt.%, respectively, with respect to TP. The optimized films showed a TS of 8.64 MPa and a % El of 52.45. WVTR of the optimized film was 55.715 g/m 2 /h. Without PVA, the optimized films showed reduced values of TS (7.21) and % El (51.67), and increased values of WVTR (56.66 g/m 2 /h), highlighting the reinforcing role of PVA in improving barrier and mechanical properties. The optimized films with PVA underwent 43.72% weight loss at the end of 28 days. Moisture sorption isotherm (MSI) studies at 35°C were best described by the Peleg model in this study. FTIR analysis confirmed the formation of intermolecular crosslinking interactions of glutaraldehyde with PVA and TP, while SEM revealed surface roughness upon PVA incorporation. XRD patterns indicated similar patterns, while DSC analysis demonstrated slightly increased melting temperature with PVA incorporation.