Engineering crystalline architecture in PLA/PBAT-based blend films through PDLA and talc for high-performance...

The limited thermal stability, barrier performance, and inherent brittleness of polylactic acid (PLA) films restrict their widespread use in sustainable food packaging applications compared with conventional polyolefins. Although blending PLA with the compostable polymer poly(butylene adipate-co-terephthalate) (PBAT) is an effective approach in improving flexibility and melt processability, the intrinsically low crystallinity of PLA persists, resulting in suboptimal thermal and barrier properties. To address this challenge, a scalable dual-nucleation strategy was developed by combining poly(D-lactic acid) (PDLA)-induced stereocomplex crystallization with talc-promoted heterogeneous nucleation to enhance the crystallization behavior and functional performance of PLA/PBAT blend films. Films with varying PDLA and talc contents were fabricated via industrially relevant blown film extrusion. FTIR, XRD, and DSC analysis confirmed the formation of thermally stable PLA stereocomplex crystals in the presence of PDLA, leading to increased crystallinity. The addition of talc further accelerated heterogeneous nucleation, promoting faster crystallization and more compact crystalline structures in both the PLA and PBAT phases. In the modified film, improved mechanical properties and thermal stability were observed, while barrier measurements revealed reduced water vapor and oxygen transmission rates. Accelerated shelf-life testing of banana chips stored at 45 °C for 23 days confirmed better moisture control, texture retention, and oxidative stability. Overall, this work establishes PDLA-talc nucleated PLA/PBAT films as a sustainable, bio-based packaging candidate for food applications.