Preparation and characterization of compatible thermoplastic starch/polyethylene blends

Compatible thermoplastic starch (TPS)/linear low density polyethylene (LLDPE) blends were prepared by one-step reactive extrusion in a single-screw extruder and characterized by means of mechanical properties, thermogravimetry (TG), scanning electron microscopy (SEM), rheological properties and Fourier transform infrared spectroscopy (FTIR). The thermal plasticisation of starch and its compatibilising modification with polyethylene were accomplished simultaneously in a single-screw extruder. The FTIR analysis showed that maleic anhydride (MAH) could graft onto the polyethylene chain using the same operational conditions as the preparation of the blends. The blends with MAH had better mechanical properties than the blends without MAH. From TG analysis, we concluded that the thermal stability of the compatible blends was higher than the incompatible blends. The FTIR results also indicated that with the addition of MAH, the compatibility between thermoplastic starch and polyethylene in the blends was truly improved.