Studies of biodegradable thermoplastic amylose/kaolin composites: Fabrication, characterization, and properties

Biodegradable thermoplastic amylose/kaolin composites (BTAKC) have been fabricated from glycerol‐plasticized amylose (GPA) and inorganic reinforced materials kaolin. Fourier Transform infrared (FTIR) patterns showed that in the BTAKC the CO groups of amylose molecules shifted to the higher wavenumber, while the reactive hydroxyl groups of kaolin in BTAKC shifted to the lower wavenumber. This was caused by the cooperation of strong absorption that existed between kaolin and amylose molecules and hydrogen bonds that formed between the reactive hydroxyl groups of kaolin and the hydroxyl groups of amylose molecules. Kaolin was on the submicron filling transition state and acted as an obstructer. Thermogravimetric analysis (TGA) showed that the mass loss of GPA and BTAKC with 20% kaolin were 15.54 and 13.74% respectively, the thermal stability of BTAKC were improved. When BTAKC was stored for 10 days at Relative Humidity (RH) = 50%, the tensile stress, strain, Young's modulus and breaking energy of BTAKC with 20% kaolin were 9.53 MPa, 65.4%, 149.8 MPa and 1.402 N m respectively. It was obvious that the mechanical properties of BTAKC were greatly improved. X‐ray diffraction revealed that kaolin restrained the crystallization of GPA effectively. Water absorption testing indicated that the introduction of kaolin reduced the water absorption of BTAKC, which greatly improve the application property of BTAKC. Scanning electron microscope (SEM) revealed that kaolin was commendably dispersed in GPA. Polym. Compos. 27:309–314, 2006.