Sustainable composites from biodegradable poly(butylene succinate) modified with thermoplastic starch and poly(butylene adipate-co-terephthalate): preparation and performance

In this article, glycidyl methacrylate (GMA) was grafted on poly(butylene succinate) (PBS) by virtue of reactive blending in the extrusion process and thermoplastic starch (TPS) was prepared via a melt blend process with anhydroxylitol tripelargonate (AXP) as a bio-based plasticizer and starch as a polymer matrix. A ternary blend of fully biodegradable polymers, namely PBS-g-GMA, thermoplastic starch and poly(butylene adipate-co-terephthalate) (PBAT), was successfully fabricated in an attempt to achieve novel entirely biodegradable composites with good comprehensive properties. The mechanical properties, rheological behavior, thermal behavior, crystallization properties and microscopic morphology of PBS-g-GMA/TPS/PBAT composites were investigated in detail. The incorporation of 30 wt% TPS into the PBS-g-GMA/TPS composite promoted a dramatic increase of 47% in the Izod impact strength of the PBS, which indicated that our work proposed an efficient route to fabricate PBS composites with good properties by a simple, eco-friendly, and low-cost processing methodology. DMA results showed that the loss factor of the composite was dependent on the TPS amount, meanwhile, with the increase of PBAT, the glass transition temperature (Tg) was more affected. The change in storage modulus indicates that the addition of TPS can improve the elasticity and the degradation of elastic properties due to the addition of PBAT. Analysis of the rheological results showed that the storage modulus (G′), loss modulus (G′′) and complex viscosity increased significantly with increasing PBAT and TPS amount which could enhance their processability. SEM indicated that PBAT was compatible with the system, and the appearance of particles at a high TPS amount confirmed the occurrence of phase separation.