The influence of citric acid on the properties of thermoplastic starch/linear low-density polyethylene blends

The effects of citric acid (CA) on the properties of glycerol/starch/linear low-density polyethylene (LLDPE) blends were studied. The plasticization of starch and its blending with PE were accomplished in one-step processing. The presence of CA improved the dispersion and the plasticization of starch, shown by scanning electron microscope (SEM). At the same time, the mechanical properties of the blends dramatic increased. The rheological study proved that acidic CA could decrease the shear viscosity and improve the fluidity of TPS/PE blends. Fourier transform infrared (FT-IR) spectroscopy proved that CA could weaken the interaction of starch molecules and improve the plasticization of starch. The X-ray diffractometry showed that starch was plasticized more completely in the CATPS/PE blends. CA could also ameliorate the water resistance of TPS/PE blends at different relative humidities.