Development of Interphase‐Engineered Poly(butylene succinate)‐Rich Bionanocomposites Reinforced With Carbon Nanotubes for Improved Structural and Functional Properties

ABSTRACT Poly(butylene succinate) (PBS) is a promising biodegradable polyester, but its broader application is limited by low toughness, slow crystallization, and poor thermal stability. Here, a PBS‐rich bionanocomposite system was developed through dual‐elastomer toughening and low‐loading carbon nanotube (CNT) reinforcement. PBS was melt‐blended with bio‐based poly(ether‐block‐amide) (PEBA) and thermoplastic polyurethane (TPU), followed by incorporation of CNTs (1–3 phr), resulting in significant improvements in mechanical, thermal, electrical, and rheological properties. Microscopic observations revealed preferential CNT localization at PBS/PEBA/TPU interphases, leading to improved phase compatibility and interfacial adhesion. CNTs acted as nucleating agents for PBS crystallization and increased the melting temperature by up to 3°C. Compared with the unfilled blend and neat PBS, the composite containing 3 phr CNT exhibited increases of 45°C and 24°C, respectively, in the temperature at 20 wt% weight loss. The optimized CNT‐reinforced composite exhibited an elongation at break more than five times higher than that of neat PBS while maintaining moderate stiffness. Electrical resistivity decreased by ~10 orders of magnitude owing to the formation of conductive CNT pathways. Rheological analysis indicated increased viscosity and elasticity, confirming enhanced interfacial interactions. These findings demonstrate a scalable approach for producing PBS‐rich bionanocomposites with enhanced toughness, thermal stability, and electrical conductivity.