Effect of thermoplastic starch content on the properties of poly(butylene adipate-co-terephthalate) (PBAT) composites

Thermoplastic starch (TPS) was evaluated as a filler in a poly(butylene adipate-co-terephthalate) (PBAT) matrix. The effect of different levels of TPS (0%, 10%, 30%, 50%) on the composite was studied. The TPS/PBAT composites were prepared by melt blending modification and high temperature moulding. The mechanical properties, hygroscopicity, water absorption, thermal stability, and micromorphology of the PBAT-based composites were tested. The results showed that the tensile strength of TPS/PBAT composites decreased from 13.7 to 3.83 MPa when the TPS content was increased from 0 wt% to 50 wt%; the flexural and tensile strengths of the composites with the addition of 10 wt% TPS were increased by 14.9% and 16.3%, respectively, compared to those of pure PBAT. The water absorption, moisture absorption balance and contact angle of the composites were improved and the contact angle of the 30 wt% TPS/PBAT composites reached 108 deg. The addition of TPS reduced the coefficient of linear expansion of the composites, which showed better thermal stability. The results are important for the development of new biodegradable composites.