Dynamic Bonds Reinforced Polyamide Elastomer for Biomedical Orthosis

Area of Science:

• Materials Science
• Polymer Chemistry
• Additive Manufacturing

Background:

• 4D printing of shape memory polymers (SMPs) offers adjustable structures but faces challenges like mechanical anisotropy and poor interlayer adhesion.
• These limitations hinder the performance and application of 4D-printed SMPs in intelligent devices.

Purpose of the Study:

• To develop a multifunctional intelligent orthosis using 4D printing technology.
• To enhance the mechanical and shape memory properties of 4D-printed SMPs by addressing interlayer adhesion and anisotropy.

Main Methods:

• Developed a dynamic bonds (DBs) reinforced shape memory polyamide elastomer via reactive extrusion using a twin-screw extruder.
• Introduced dynamic covalent networks, including dynamic covalent bonds (DCBs) and hierarchical hydrogen bonds (DHBs), to improve interlayer adhesion.
• Utilized 4D printing technology to fabricate the intelligent orthosis.

Main Results:

• The developed elastomer exhibited enhanced interlayer adhesion, significantly reducing mechanical anisotropy in 4D-printed objects.
• The 4D-printed materials demonstrated improved mechanical properties and superior shape memory performance.
• The study successfully demonstrated the material's versatility and its application in a spinal orthosis.

Conclusions:

• The integration of DBs into shape memory polyamide elastomer effectively enhances interlayer adhesion and mechanical properties for 4D printing.
• This approach overcomes key limitations in 4D-printed SMPs, enabling advanced functionalities and applications like intelligent orthoses.