Enhanced performance of PBAT/starch biocomposites through compatibilization and carbon black for outdoor applications

This study aimed to enhance the interfacial compatibility, processability, mechanical durability, and UV stability of biodegradable poly (butylene adipate-co-terephthalate) (PBAT)/starch composite films by incorporating polyglycerol ester (PGE) as a dual-function additive and carbon black (CB) as a UV stabilizer. In this work, PGE (2.5 and 5 wt%) and CB (1.5 phr) were incorporated into the PBAT/starch matrix. The addition of 2.5 wt% PGE increased tensile strength and elongation at break by 30.2% and 42.5%, respectively, compared with the PBAT–5PGE. After 60 days of Q-SUN exposure, the PBAT–2.5PGE–CS–1.5CB sample retained 88% of its tensile strength and 83% of its modulus, whereas CB-free films lost more than 30%. 1 H NMR analyses confirmed reduced oxidation and chain scission in CB-containing systems. Additionally, the water contact angle increased from 59.01° to 88.11°, indicating enhanced surface hydrophobicity. These results demonstrate that PGE acts as both a compatibilizer and plasticizer, while CB serves as an effective UV shield, leading to superior structural integrity and outdoor durability of PBAT/starch films.