Starch-based biomass composites were prepared with starch and plant fiber. In order to improve the properties of the compos ites, oxidized starches (OS) were prepared using hydroxyl peroxide as oxidizer, then glycerol was added into OS as plasticizer to produce thermoplastic oxidized starches (TPOS). Crystal structure, hydrogen bonds of TPOS were researched to gain comprehensive views on the mechanism of the property differences between the starch-based composites with native starch, OS and TPOS. The changes of crystal structure were analyzed by X-ray diffraction analysis. Starch intermolecular hydroxyl changes were investigated using the method of infrared spectrum analysis. It was found that the new hydrogen bonds were formed between the plasticizer, oxidizer and starch, and the starch intermolecular bonding force was weakened. The structure of sta ch crystallization was destructed in TPOS. Differential scanning calorimetry showed that cross reaction with oxidization and plasticization changed the crystal structure, glass transition process was not observed in TPOS. The tensile and compressive strengths of composite based on TPS were improved greatly and mechanical properties were not weakened obviously with water content increased. All the results indicated that TPOS could improve the properties of starch-based composites.

Chuan-Wei Zhang, Fang-Yi Li, Jian-Feng Li, Qi Xie, Jie Xu, An-Fu Guo, and Cheng-Zhao Wang