Enhancing PLA/ABS Blends Compatibility: A Comparative Study With SAN‐Epoxy and SAN‐MA

ABSTRACT Blends of poly (lactic acid) (PLA) with acrylonitrile‐butadiene‐styrene (ABS) were prepared using styrene–acrylonitrile copolymers functionalized with maleic anhydride (SAN‐MA) and epoxy (SAN‐Epoxy) as compatibilizers. The blends were processed in an internal mixer and injection molded. Analyses included torque rheometry, dynamic oscillatory shear rheology, impact resistance, tensile strength, Shore D hardness, heat deflection temperature (HDT), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Rheological tests showed increased torque and viscosity in PLA/ABS blends, particularly with SAN‐Epoxy, indicating better phase compatibility. The incorporation of 10 phr (parts per hundred resin) of SAN‐Epoxy into the PLA/ABS blend (70/30% by weight) increased impact resistance by approximately 200% compared to pure PLA. Additionally, it promoted better performance in tensile modulus and tensile strength compared to the system compatibilized with SAN‐MA. SEM analysis revealed that ABS particles in the PLA matrix had more stable size and distribution with SAN‐Epoxy, explaining the favorable mechanical results. The Shore D hardness and HDT of the PLA/ABS/SAN‐Epoxy blends remained unchanged compared to PLA, suggesting a balance of properties. Overall, SAN‐Epoxy proved to be the most effective compatibilizer, indicating greater interaction with the phases, thereby contributing to improved mechanical and thermal performance.