Reinforced PBAT/PLA Foams With Lignin as a Bio‐Based Nucleating Agent for High‐Performance Building Insulation

ABSTRACT Low melt‐strength poly(butylene adipate‐co‐terephthalate) (PBAT) foams suffer from poor pore stability, which significantly limits their practical applications. To overcome this limitation, enhancing the melt strength of PBAT‐based composites is essential for improving the stability of foamed materials. In this study, PBAT/PLA/lignin composite foams were prepared using a chemical hot‐pressing method, with PBAT, PLA, and lignin as raw materials and azodicarbonamide (AC) as the blowing agent, aiming to develop renewable materials with favourable mechanical properties and thermal conductivity. The addition of PLA positively influenced the mechanical properties of the composites, while the complex molecular structure and rigidity of lignin resulted in lower thermal conductivity and enhanced mechanical properties. The results demonstrated that incorporating 20 wt% PLA and 10 wt% lignin into PBAT produced a uniform and fine pore structure. The resulting composite exhibited a homogeneous, fine‐cell morphology, with a thermal conductivity of 0.100 W/(m·k), and impact and compressive strengths of 12.41 kJ/m 3 and 12.91 MPa, respectively. These combined attributes make the composite a promising candidate for building insulation applications.