Preparation, reinforcement and properties of thermoplastic starch film by film blowing

Starch is considered as the most promising material of biodegradable polymer films. However, up to date, the preparation of starch film by film blowing technique is still a challenge. Herein, cassava starch, glycerol and nano-silica (nano-SiO2) were used to prepare thermoplastic starch (TPS) films by film blowing technique. The effects of glycerol and nano-SiO2 on the mechanical properties, thermal properties and structure of TPS films were investigated. The results showed that the elongation at break of the TPS film with 40 parts of glycerol per 100 parts of dried starch (40 phs glycerol) was up to 108%. After the addition of 1 part of nano-SiO2 per 100 parts of dried starch (1 phs nano-SiO2), the tensile strength significantly increased by about 95%, while the elongation at break did not decrease. The thermal stability of starch increased with the increase of glycerol and nano-SiO2, while its melting transition temperature did not change significantly. The crystalline structure of starch changed after processing, and the crystallinity of starch decreased with increasing glycerol and nano-SiO2.