Reactive Compatibilization of Bio-Based PLA/PEF Blends for Recoverable 4D-Printed Architectures

Abstract

Fused deposition modeling (FDM) of shape-memory polylactic acid (PLA) offers opportunities for thermally responsive architectures, but its brittleness limits structural applications. Here, predominantly bio-based PLA/poly(ethylene furanoate) (PEF) blends were developed using a multifunctional epoxy-based chain extender (ADR) for reactive compatibilization. Molecular dynamics simulations and scanning electron microscopy indicated limited thermodynamic compatibility and interfacial defects in uncompatibilized blends. Adding 0.1–0.3 wt % ADR to a PLA/PEF blend with polymer mass ration of 90/10 refined the dispersed morphology and increased low-frequency melt elasticity, consistent with improved interfacial coupling. The characteristic PEF-domain diameter decreased from 0.55 to 0.20 μm. The blend containing 0.1 wt % ADR produced an elongation at break of 10.8%. ADR increase the shape recovery ratio of bent specimens from 73.7% to 87.0%. Gyroid and Diamond triply periodic minimal surface architectures printed from the blend containing 0.1 wt % ADR exhibited sustained compressive load-bearing behavior and recovery ratios of 92.13% and 89.25%, respectively. These findings demonstrate a predominantly bio-based material approach for recoverable 4D-printed architectures, which highlight the potential in thermally-responsive engineering architectures including deployable energy absorbers and biomedical components.