Bio-based polymer pellets and tubular films derived from agro-industrial residues

In this work pellets and tubular blown films were developed from potato starch plasticized with a bio-based viscous black liquid obtained through solvolysis of corn stover. The methodology of the experimental study encompassed the evaluation of premixes, blends, pellets and tubular films elaborated. The black liquid was mixed at room temperature with starch at different compositions, obtaining premixes capable of being processed in a torque rheometer under certain conditions of temperature and time and at constant rotational speed. Starch-glycerol blends were used as control samples. From the results obtained (maximum torque, stickiness) the most suitable composition and its optimum processing conditions were chosen for upscaling to pilot level. At pilot scale, pellets of the selected materials were obtained by extrusion processes, and then used in a film blowing machine to obtain bio-based films. Tensile properties of the final products were measured. This study allowed identifying processing parameters to obtain pellets and films at a pilot scale (140 °C, 90 rpm), and to determine the mechanical performance of the final products under tensile solicitations. Therefore, the results confirmed that bio-based plasticizer is able to provide the native starch with suitable properties to transform it into pellets and tubular blown films.