Simultaneously enhancing toughness and stiffness for biodegradable poly (butylene succinate) modified with poly (butylene adipate-co-terephthalate) and starch plasticized with erythritol tetranonanoate

Abstract

In this article, erythritol tetranonanoate (ETNT), synthesized through erythritol extracted from agro-food industry waste through various green processes with nonanoic acid, as the saccharide-based plasticizer, is applied to starch to prepare thermoplastic starch (TPS). A series of biodegradable PBS blends are fabricated through the melt blending with TPS and Glycidyl methacrylate (GMA) grafted poly (butylene adipate-co-terephthalate) (PBAT), namely PBAT-g-GMA, in an attempt to simultaneously enhance the toughness and stiffness of the result materials. In this work, the resulting biodegradable PBS blends are in detail studied from the perspectives of mechanics, thermal properties, rheology, crystallization and morphology. The structure of ETNT is confirmed by Fourier transform infrared spectroscopy (FTIR) and Nuclear magnetic resonance (¹H NMR). Incorporating 50 wt% TPS into the blends results in a remarkable increase of 125% in the Izod impact strength and 18% in the Young’s modulus compared to pure PBS, demonstrating that our proposed strategy is efficient for preparing PBS blends with good comprehensive properties through a straightforward, environmentally friendly, and cost-effective processing method. The DSC result indicates that the addition of TPS at 50% leads to a crystallinity of 24.1% in the blends, which is 66.1% lower than that of PBS. Rheological analysis reveals that the storage modulus (G'), loss modulus (G"), and complex viscosity increase significantly with higher amounts of PBAT-g-GMA and TPS, indicating improved processability. SEM shows that the addition of PBAT-g-GMA progressively homogenizes the blends and enhances the bonding between TPS and the matrix.