Mixture design applied to evaluating the effects of polyvinyl alcohol (PVOH) and alginate on the properties of starch‐based films

Abstract

Mixtures of starch and other polymers have been used to produce biodegradable materials with low‐cost and enhanced properties. In this study, films containing starch mixed with alginate (ALG) and/or polyvinyl alcohol (PVOH) were characterized. Films produced using binary starch–alginate mixtures (F3, F5, and F9) had the highest tensile strength (19–28 MPa) and elongation capacity (22–17%). However, films produced using ternary starch–alginate–PVOH mixtures (F8 and F9) exhibited the best water‐barrier efficacy, with lower water‐vapor permeability (WVP) values (5 × 10 and 5.56 × 10−13 g/s/Pa/m1, respectively) than that of the starch films (23.60 × 10−13 g/s/Pa) and diffusion coefficient (Dw) values approximately seven times lower than that of films produced solely with starch. The results of the infrared analyses showed a decrease in the band representing OH stretching in films created using ternary starch–alginate–PVOH mixtures, suggesting interaction between the polymers. The films containing starch mixed with ALG and PVOH showed low monolayer. The results indicated that ternary blends created better physical barriers to the passage of water vapor and diminished the availability of active sites for water binding. The optimal proportions were found to be 80% starch, 11.4% ALG and 8.6% PVOH.