Thermoplastic starch modified with hydrophobic polyurethane microparticles

Modified thermoplastic starches (TPS) were successfully prepared from corn starch (CS) and hydrophobic polyurethane prepolymers (PUPs) by solid-state reactions under intensive mixing conditions. The structure and properties were investigated using FTIR, SEM, wide-angle XRD, tensile testing machine, Brookfield viscometer, and contact angle (CA) meter. The results showed that 98.6 +/- 0.4% of PUP was cross-linked to starch, suggesting a high efficiency of the solid-state reaction. Compared with unmodified starch, the hydrophobic property of the modified TPS was improved, resulting in an increase of the CAs and a decrease of the Brookfield viscosity. Morphology analysis indicated that the modified starch exhibited increased compatibility between the PUP particle and nature starch, leading to the increased elongation at break.