Effects of different sources of cellulose on mechanical and barrier properties of thermoplastic sweet potato starch films

Abstract

Sweet potato starch and different celluloses were mixed by thermoplastic extrusion and then thermoplastic starch/cellulose composite films were prepared using a casting method. The effect of different celluloses on the mechanical and barrier properties of thermoplastic sweet potato starch films were studied and compared. The results indicated that among thermoplastic starch/cellulose composite films, the hydrogen bond interaction between starch and sugarcane cellulose was more obvious and the crystallization melting temperature difference was smaller, indicating better compatibility between sugarcane cellulose and sweet potato starch. Thermoplastic starch/sugarcane cellulose film had the largest FTIR ratio values of 1047 cm−1/1022 cm−1, resulting in the highest tensile strength (3.75 MPa), largest contact angle (68.44°), or stronger surface hydrophobicity. Thermoplastic starch/cornstalk cellulose film had the highest thermal degradation temperature (325 °C). Thermoplastic starch/wheat or bamboo cellulose film had lower UV transmittance (about 36%), indicating stronger UV Resistance. Thermoplastic starch/rice bran cellulose film had the largest elongation at break value (49.03%). Thermoplastic starch/bamboo or cornstalk cellulose films had lower water vapor permeability, whereas thermoplastic starch/rice bran cellulose had higher water vapor permeability. The outcoming would provide a new theoretical basis for choosing an optimal cellulose compatible with thermoplastic sweet potato starch to enhance mechanical properties, water resistance and barrier property of thermoplastic starch films.