Physical and chemical characterization of a biopolymer film made with corn starch and nopal xoconostle (opuntia joconsotle) mucilage

Abstract

Two kinds of biopolymer films were made from mucilage nopal xoconostle (Opuntia joconostle), corn starch, polyvinyl alcohol, chitosan and glycerol, which were prepared by the casting/solvent evaporation method. A comparison between the formed films using the mucilage extract and the direct addition of mucilage to the polymer matrix was discussed. The FTIR analysis revealed that both biofilms possessed a similar chemical structure. The thermal behaviour of the two kinds of films resulted very similar with an initial thermal decomposition temperature around at 156 °C. Optical and SEM microscopies showed that the total solids present in the directly-added mucilage formed microphases in the bulk of the films. The mechanical properties disclosed that the higher the content of plasticisers the lower the elastic modulus and hardness values when mucilage was added directly.