Continuous Additive Manufacturing using Olefin Metathesis

Area of Science:

• Polymer Chemistry
• Materials Science
• Additive Manufacturing

Background:

• Olefin metathesis polymerization offers unique advantages for polymer synthesis.
• Additive manufacturing (AM) requires precise control over polymerization kinetics.
• Developing selective polymerization methods is crucial for advanced AM techniques.

Purpose of the Study:

• To develop a selective dual-wavelength olefin metathesis polymerization process for continuous additive manufacturing.
• To enable precise control over initiation and deactivation using distinct light wavelengths.
• To adapt the process for both 2D stereolithography (SLA) and 3D continuous AM.

Main Methods:

• Formulation of a dicyclopentadiene-based resin with a latent olefin metathesis catalyst.
• Incorporation of photosensitizers (PSs) and photobase generators (PBGs) for wavelength-specific activation and deactivation.
• Utilizing dual-wavelength light (e.g., blue and UV) to control polymerization initiation and termination.
• Application in 2D SLA printing with photomasks or patterned light, and 3D continuous AM.

Main Results:

• Successful implementation of selective dual-wavelength olefin metathesis polymerization.
• Efficient initiation achieved with one wavelength (e.g., blue light).
• Rapid catalyst decomposition and polymerization deactivation achieved with a second wavelength (e.g., UV light).
• Demonstrated 2D SLA printing capabilities.
• Achieved 3D continuous AM printing rates of 36 mm/h with patterned light and up to 180 mm/h with high-intensity, un-patterned light.

Conclusions:

• The developed dual-wavelength olefin metathesis polymerization is a versatile technique for additive manufacturing.
• This method allows for precise spatiotemporal control over polymerization, crucial for complex 3D structures.
• The process demonstrates high printing speeds, making it suitable for efficient continuous additive manufacturing.