2026/01/01 by Zhenfu Liu, Long Chen, Lu Ls +4 · 1 voice
Materials Science · Engineering · #Polymer composites and self-healing #Advanced Materials and Mechanics #Additive Manufacturing and 3D Printing Technologies
paper · doi:10.1515/ntrev-2025-0334
openalex publication_date 2026/01/01 · openalex created_date 2026/07/22 · openalex updated_date 2026/08/01
Abstract Shape memory polymers (SMPs) can actively transform their shape or properties upon exposure to external triggers. Among these materials, polylactic acid (PLA) draws significant research interest owing to its superior shape memory behavior. However, reconciling shape memory performance with mechanical properties remains challenging due to the inherent brittleness of PLA. This study aims to improve the actuation speed and mechanical performance of 4D-printed PLA-based structures. By direct melt blending of PLA, PBAT, and CNTs, a thermally responsive 4D-printable composite filament was successfully fabricated. The thermal-responsive shape memory behavior and mechanical properties of the printed specimens were thoroughly investigated. The results demonstrate that by optimizing the blending process, 1.0 wt% CNT is uniformly dispersed within the PLA/PBAT matrix. The formulation forms a continuous thermally conductive network, boosting both mechanical strength and shape recovery speed. This enhancement is attributed to the significantly improved CNT dispersion and interfacial bonding achieved through process optimization. All composites exhibit high shape fixity ( R f ≈ 98.3 %) and shape recovery ( R r ≈ 93 %). Notably, the enhanced thermal conductivity significantly accelerates the shape memory response. The composite containing 1.0 wt% CNT achieves complete recovery within only 8 s when heated in a water bath at 65 °C. In the present study, a CNT-reinforced PLA/PBAT composite was engineered to achieve a combination of superior mechanical properties and rapid thermal-responsive shape recovery capacity, which can be widely applied in soft actuators and robotics.