Morphological, thermal, and mechanical studies of film elaborated with the blend low-density polyethylene and chemical-modified banana starch

Films were prepared by extrusion acetylated and oxidized banana starches at different concentration mixed with low-density polyethylene. Morphological, mechanical, and thermal characteristics of the films were tested. Irregularities in the films prepared with native and oxidized banana starches were observed by scanning electron microscopy. This pattern is maybe due to the incompatibility between both polymers. However, films elaborated with acetylated banana starch showed a smooth surface. The tensile strength and elongation at break decreased when starch level in the blend increased. An inverse pattern was showed for elastic module. The effect on mechanical properties was more notorious in those films elaborated with the acetylated and oxidized banana starches. Two thermal transitions were observed by differential scanning calorimetry, the principal transition at ∼ 111°C was due to disorganization of the low-density polyethylene. Enthalpy value associated to that principal transition was higher in the films elaborated with acetylated banana starch, showing higher compatibility between both polymers. The use of biodegradable polymers such as chemically modified banana starch might be feasible for elaboration of films with adequate mechanical properties.