Effect of alkali-treated Putranjiva roxburghii seed shell filler on physico-chemical, thermal, mechanical, and barrier properties of polyvinyl alcohol-based biofilms

Biopolymers and bio-fillers derived from natural, organic, and abundant resources have garnered more responsiveness owing to their affordability and degradability in the production of packaging plastics. This study explores the novel use of different proportions (5%, 10%, 15%, and 20%) of 5% alkali-treated Putranjiva roxburghii seed shell filler (PRSSF) as a bio-filler in combination with polyvinyl alcohol (PVA) for the first time. FTIR analysis showed the creation of robust hydrogen bonds and enhanced compatibility between the matrix and the alkalized PRSSF. The XRD results revealed that alkalized PRSSF strengthens the structural integrity of biofilms. The water absorption of the PVA/at PRSSF biofilm samples decreased by 88.38% at a higher composition (20%) of alkali-treated PRSSF due to their alkalized hydrophobic filler. Due to the effect of at-PRSSF into PVA, the resulting films demonstrated a degradation temperature and char residue of 334.8°C and 13.57%, respectively, and relatively better UV-barrier properties in a range of visible light. When compared with pure PVA films, the tensile strength and corresponding modulus of PVA/20% at-PRSSF films increased by 32.94% and 16.2%, respectively. Therefore, the PVA/at-PRSSF biofilms produced in this study are ideal materials for wrapping and folding applications.

Highlights

• PVA/at-PRSSF films outperform in multiple aspects as compared with pure PVA.
• Tensile strength of PVA/20%-PRSSF films increased by 32.94%.
• Elongation at break decreased with at-PRSSF loading.
• Water absorption in PVA/20% PRSSF biofilm decreased by 88.38%.
• Fractography showed voids and agglomerations at high filler levels.