Effect of Boric Acid on the Properties of Sorbitol Plasticized Starch/PVA Blends

Abstract

This research aimed to focus on the thermochemical and physico-mechanical properties along with biodegradability nature of partially pregelatinized maize starch (PMS) and polyvinyl alcohol (PVA) based biocomposites. Several PMS/PVA/BA (varying the mass ratio, wt %) based biocomposites were prepared by solution casting with and without sorbitol plasticizer. Boric acid (BA) used as cross linked agent. The FT-IR, DSC and TGA results revealed that the hydrogen bonding takes place between PMS and PVA in presence of BA and thus biocomposites shown more thermal stability than that of pure PMS and PVA provided by TGA and DSC. Based on the results, sorbitol plasticized PMS/PVA/BA (5%) was optimized as pliable and stable biocomposite; the tensile strength (TS)and percentage of elongation at break (EB%) was 16.6 MPa and 11.2 % respectively. However, unplasticized biocomposites shown the highest TS (38.1 MPa) but were hard and brittle. Moreover, the optimized biocomposite was the lower moisture sensitivity and moderate water solubility compared to other biocomposites. In addition, the biodegradability nature of biocomposites were also investigated and found it biodegradable. Thus, the optimized biocomposite (PMS: PVA: BA with a ratio of 40:55:5) can be used as effective and eco-friendly packaging material.