Shape memory performance of bio-based polyester blends 4D printed by Fused Granulate Fabrication (FGF)

Artikel i vetenskaplig tidskrift, 2026

With the rise of advanced manufacturing technologies such as Fused Granulate Fabrication (FGF), the influence of processing routes on the shape-memory behavior of bio-based polymers remains poorly understood. This study investigates poly(hydroxybutyrate) (PHB)/poly(lactic acid) (PLA)/poly(butylene succinate- co -adipate) (PBSA) biopolyester blends 3D-printed using FGF under varied programming conditions to establish structure–process–property relationships relevant to 4D printing. Comparing compression-molded and printed samples revealed how fabrication and printing-induced orientation affect morphology, mechanical properties, and the shape memory effect (SME) response. PLA75-PBSA25 demonstrated superior mechanical performance (strength ≈40.00 MPa, modulus ≈1.10 GPa) and SME efficiency, achieving nearly perfect shape fixity (Rf ≈ 100%) and high recovery (Rr ≈90.0%). Based on combined SME and mechanical performance, the blends can be ranked as: PLA75-PBSA25 > PHB25-PLA50-PBSA25 > PHB33-PLA33-PBSA33 > PHB50-PLA25-PBSA25 > PHB75-PBSA25. Programming temperature had a significant influence on SME: cold programming resulted in incomplete fixation, hot programming caused partial loss of recovery due to plastic deformation, while warm programming (60 °C) yielded the most balanced and repeatable performance. 3D-printed samples retained SME efficiency within 10.0% of that of compression-molded counterparts. Layers printed parallel to the deformation direction exhibited slightly higher recovery than those printed at 90°. Cyclic testing confirmed that PLA75-PBSA25 retained stable SME performance over 15 cycles, while other blends exhibited moderate fatigue. Overall, optimized phase compatibility and warm-programming conditions enabled the reliable synthesis of SME, identifying PLA75-PBSA25 as a promising material for durable 4D-printed shape memory applications.