Processing‐Structure‐Property Relationships in Kenaf Fiber‐Reinforced <scp>PLA</scp> / <scp>PBAT</scp> Composites: The Role of Reinforcement in Mechanical and Morphological Performance

ABSTRACT The increasing demand for sustainable and biodegradable materials has driven the development of bio‐based polymer composites as alternatives to petroleum‐based plastics. However, optimizing the interfacial interaction between the polymer matrix and natural fibers remains a key challenge. In this study, PLA/PBAT composites reinforced with 5 wt% kenaf fiber were fabricated using three compounding sequences to investigate the effect of fiber localization on composite performance. The results show that Sequence 2 (S2), where kenaf was pre‐blended with PBAT before mixing with PLA, yielded the best performance with a 68% increase in tensile strength and a 57% improvement in tensile modulus compared to the conventional direct mixing method. TGA and DSC analyses revealed improved thermal stability and suppressed PBAT crystallization due to the processing sequence. Morphological analysis confirmed better fiber dispersion and matrix interaction in S2. Water absorption results showed lower uptake in S2 composites (3.4% at 24 h) compared to S3 (5.2% at 24 h), confirming stronger matrix encapsulation and reduced voids. These findings demonstrate that tuning the compounding sequence is a simple, scalable strategy to enhance the mechanical and environmental performance of bio‐based composites, making them promising candidates for biodegradable packaging and short‐lifespan structural applications.