Compatibilization of Immiscible PLA/LDPE Blends Using SEBS‐g‐MAH: A Multiscale Approach Combining Experimental and Computational Studies

Abstract

ABSTRACT In this study, blends of inherently immiscible polylactic acid and low‐density polyethylene (PLA/LDPE, 80:20) were prepared with 0–10 wt.% SEBS‐g‐MAH (styrene‐ethylene‐butylene‐styrene grafted with maleic anhydride) as a compatibilizer. Molecular dynamics (MD) simulations probed the blends' binding energies and interaction mechanisms, while density functional theory (DFT) calculations (Density of states and COSMO‐RS) assessed the compatibilizer's effect on polymer affinity. Morphological and thermal properties were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), and scanning electron microscopy (SEM). MD results showed that SEBS‐g‐MAH significantly increased the binding interaction energy of PLA/LDPE. DOS and COSMO‐RS analyses revealed enhanced compatibility and increased affinity between PLA and LDPE when SEBS‐g‐MAH was present. TGA indicated no significant effect of SEBS‐g‐MAH on blend thermal stability, contrary to prior reports of compatibilizer‐induced degradation changes. XRD results demonstrated a reduction in crystallinity with increasing SEBS‐g‐MAH content. SEM images revealed a finer and more uniform phase morphology, as well as improved PLA/LDPE interfacial adhesion. These improvements are attributed to the amphiphilic nature of SEBS‐g‐MAH, which strengthens interfacial interactions. Overall, SEBS‐g‐MAH effectively compatibilizes PLA/LDPE blends, yielding a refined morphology, superior compatibility, and accelerated interfacial interaction compared to other compatibilizers. These findings highlight the potential of SEBS‐g‐MAH as a superior compatibilizer in immiscible PLA/LDPE blends.