Investigation of the Impact of Graft Compatibilizer Main‐Chain Structure on the Properties of PBAT / PLA Composites

ABSTRACT Poly(butylene adipate terephthalate) (PBAT) and polylactic acid (PLA) exhibit inherent thermodynamic incompatibility. To enhance the compatibility between the two phases, three kinds of graft compatibilizers with different main‐chain structures, named as PBAT‐ g ‐VCHO, PLA‐ g ‐VCHO, and PBS‐ g ‐VCHO, are synthesized by grafting 4‐vinyl epoxycyclohexane (VCHO) onto PBAT, PLA, and PBS, respectively, which employs a melt grafting approach and uses diisopropylbenzene peroxide as the initiator. The findings confirmed the successful synthesis of the three compatibilizers, and the water contact angle results showed that each of the three compatibilizers effectively reduced the interfacial tension between the PBAT and PLA phases. Specifically, the three compatibilizers are applied into PBAT/PLA composites, and the influence of the compatibilizer grafting rate and dosage on the properties of composites is discussed. Comparative analyses demonstrated that optimal performance of the composites is achieved with grafting rates of 1.64% for PBAT‐ g ‐VCHO, 1.71% for PLA‐ g ‐VCHO, and 1.56% for PBS‐ g ‐VCHO, corresponding to addition contents of 10%, 7.5%, and 7.5%, respectively. Overall, the results indicated that the PBAT/PLA composite exhibits the best comprehensive performance with the addition of the compatibilizer PBS‐ g ‐VCHO with a grafting rate of 1.56% and a content of 7.5%.