Direct Ink Writing 3D Printing Elastomeric Polyurethane Aided by Cellulose Nanofibrils.

Area of Science:

• Materials Science
• Polymer Chemistry
• Additive Manufacturing

Background:

• Flexible polyurethane elastomers are crucial for applications like soft robotics and footwear.
• Conventional 3D printing methods (FDM, VPP) have limitations in material choice for polyurethanes.
• Developing new 3D printing inks is essential for advanced elastomeric material fabrication.

Purpose of the Study:

• To synthesize a novel water-borne polyurethane ink for Direct Ink Writing (DIW) 3D printing.
• To enable room-temperature printing of complex, monolithic elastomeric structures.
• To enhance mechanical properties and durability of 3D printed polyurethane.

Main Methods:

• Synthesis of a water-borne polyurethane ink incorporating cellulose nanofibrils (CNFs).
• Direct Ink Writing (DIW) 3D printing at room temperature.
• Solvent-Induced Fast Solidification (SIFS) for room-temperature curing and property enhancement.

Main Results:

• Successfully 3D printed complex, monolithic elastomeric structures using the developed ink.
• Achieved high ultimate tensile strength (up to 22 MPa) and elongation at break (951%).
• Demonstrated excellent resilience, durability over 100 cycles, and resistance to significant mechanical stress.

Conclusions:

• The developed water-borne polyurethane ink and DIW method allow for room-temperature fabrication of high-performance elastomers.
• The incorporation of CNFs and SIFS method significantly improve mechanical properties and durability.
• This approach offers a versatile platform for 3D printing advanced flexible polyurethane structures for various applications.