Study on the effect of co-plasticization of post-industrial starch for high-impact thermoplastic starch development

Abstract

This study analyzed the effect of employing plasticized or co-plasticized post-industrial starch in developing PBAT-based thermoplastic starch (TPS) blends. In this work, the post-industrial wheat starch was co-plasticized with glycerol-urea, glycerol-citric acid, and glycerol-succinic anhydride, and then melt-extruded with PBAT to develop the TPS blends. The effect of co-plasticization was investigated by analyzing the TPS blends' mechanical, thermal, and rheological characteristics. The results showed that co-plasticized starch was more effective than solely glycerol-plasticized starch in enhancing the TPS blends' mechanical, thermal, and rheological characteristics. The TPS containing citric acid as a co-plasticizer showed increases of 246, 35, and 46% in impact strength, elongation at break, and crystallinity, respectively, compared to glycerol-plasticized starch-based TPS. Morphological analysis further revealed that the citric acid co-plasticized starch improved the dispersion and compatibility of the plasticized starch within the PBAT matrix. Overall, the study showed that adding citric acid during the co-plasticization of starch resulted in high-impact TPS blends with enhanced material properties compared to glycerol-plasticized starch and urea or succinic anhydride co-plasticized starch.