4D Printing Behavior of PETG/SEBS Blends: A Comparative Study of Reactive and Non-Reactive SEBS with Varied Styrene Content

The demand for flexible and functional materials in additive manufacturing has spurred interest in polymer blends with shape memory capabilities. PETG, though widely used in 3D printing, lacks the flexibility required for advanced applications. The incorporation of SEBS elastomers, especially those grafted with maleic anhydride (SEBS-g-MA), into PETG matrices enhances flexibility while introducing shape memory properties. This study investigates PETG/SEBS and PETG/SEBS-g-MA blends prepared via fused filament fabrication (FFF) for 4D printing. FTIR and SEM analyses revealed a co-continuous morphology for PETG/SEBS-g-MA blends, indicating good interfacial adhesion, which improved mechanical properties and shape memory performance. In contrast, PETG/SEBS blends exhibited a sea-island morphology with reduced compatibilization. Blends with 13% styrene content in SEBS showed high flexibility, with modulus values of 2–5 MPa and elongations over 230%, producing soft, elastic materials. Shape memory performance, evaluated in water and via rheometry, demonstrated near-100% recovery and fixation for all blends, with water-activated recovery outperforming torsion tests. Filaments (1.6–1.8 mm diameter) were successfully produced, enabling 4D printing applications. Blends like PETG/SEBS-g-MA (30% styrene) showed superior dimensional control and printing ease due to improved compatibilization. In conclusion, PETG/SEBS and PETG/SEBS-g-MA blends offer a significant improvement in flexibility and shape memory capabilities, making them ideal candidates for 4D printing. The combination of excellent mechanical properties, high shape recovery, and successful filament production underscores their potential for use in dynamic and adaptive printed structures.