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Dual-Stimuli Responsive and Sustainable PLA/APHA/TPU Blend for 4D Printing
Shafahat Ali1, Mamoun Alshihabi1, Logan Beard1
1Advanced Manufacturing Lab (AML) School of Engineering, University of Guelph, Guelph, Ontario, Canada.
Macromolecular Rapid Communications
|August 14, 2025
Summary
This study introduces a novel 4D printing filament blending PLA, APHA, and TPU for enhanced medical devices. The material achieves low-temperature shape memory activation with superior strength and flexibility, overcoming previous limitations.
Area of Science:
- Materials Science
- Polymer Science
- Biomedical Engineering
Background:
- Current shape memory polymers (SMPs) for 4D printing face a trade-off between mechanical toughness and low-temperature activation.
- PLA-based SMPs often exhibit brittleness, limiting their application in patient-specific medical devices.
- There is a need for advanced SMPs that combine mechanical robustness with efficient low-temperature shape recovery.
Purpose of the Study:
- To develop a novel 4D printable filament based on PLA/APHA/TPU blends.
- To achieve low-temperature shape memory activation combined with high mechanical strength and flexibility.
- To evaluate the printability, biocompatibility, and shape memory performance of the developed composite for biomedical applications.
Main Methods:
- Fabrication of a novel PLA/APHA/TPU blend filament using 3D printing.
- Characterization of the composite's microstructure, mechanical properties (tensile strength, modulus, elongation), and thermal behavior.
- Evaluation of shape memory properties, including shape fixity and recovery ratios, under thermal and mechanical stimuli.
- Assessment of printability and biocompatibility for potential biomedical uses.
Main Results:
- The optimized 60/20/20 wt.% PLA/APHA/TPU blend demonstrated uniform dispersion, enhanced tensile strength, modulus, and elongation compared to neat PLA.
- The composite exhibited rapid shape recovery at approximately 39.5°C, significantly below PLA's glass transition temperature.
- Near-complete shape fixity (∼100%) and high recovery ratios (>92%) were achieved under dual thermal and mechanical stimuli.
- The material maintained excellent printability and biocompatibility.
Conclusions:
- The developed PLA/APHA/TPU blend filament successfully overcomes the limitations of traditional PLA-based SMPs, offering a unique combination of mechanical toughness and low-temperature shape memory activation.
- The synergistic effects of TPU and APHA contribute to the material's enhanced ductility, flexibility, and thermal sensitivity.
- This novel material holds significant promise for next-generation 4D-printed biomedical devices, including orthopedic braces, soft robotic actuators, and adaptive implants.
- The use of bio-based, biodegradable polymers advances eco-friendly additive manufacturing for high-performance SMPs.
