Tuning the Mechanical Properties of Poly(butylene xylosediglyoxylate) via Compounding Strategies

Producing high-performance materials from renewable carbon at high efficiency and ensuring a sustainable end-of-life scenario can notably reduce the CO2 footprint of the plastics industry. A recent example of such a material is poly(butylene xylosediglyoxylate) (PBX), a xylose-based polyester made in high yield from the hemicellulosic fraction of biomass. The well-rounded performance of PBX in terms of tensile strength, glass-transition temperature, and gas permeability makes it suitable for a range of market applications. However, PBX tends to be brittle (elongation at a break of 9.8%), depending on the manufacturing process. Herein, the rational tuning of PBX's flexibility was investigated using compounding strategies with additives and the commercially available polyesters poly(butylene succinate) and poly[(butylene adipate)-co-(butylene terephthalate)] (PBAT). While the use of additives failed to improve the flexibility of PBX, the blending approach with PBAT led to materials with improved flexibility while retaining excellent thermomechanical and barrier properties. For example, the blending of PBX with 20 wt % PBAT led to elongations of break of 148% while maintaining a 1.6 GPa tensile modulus, a main glass transition of 89 °C, and only moderately disrupted barrier properties (OTR100 μm = 18 cm3/m2/day and WVTR100 μm = 44 g/m2/day). This advancement establishes a pathway toward the creation of biobased, flexible packaging materials with sustainable end-of-life.