Material Extrusion Additive Manufacturing with Polyethylene Vitrimers

Area of Science:

• Polymer Science
• Materials Science
• Additive Manufacturing

Background:

• Polyethylene (PE) is widely used but difficult to 3D print due to poor adhesion and shrinkage.
• These limitations result in anisotropic parts, poor dimensional accuracy, and warpage.
• Vitrimers offer a solution with dynamic crosslinked networks, enabling reprocessing and improved thermal stability.

Purpose of the Study:

• To investigate the 3D printability of high-density polyethylene vitrimers (HDPE-V).
• To evaluate the impact of HDPE-V on dimensional stability and mechanical anisotropy during additive manufacturing.
• To assess the potential for post-processing via annealing.

Main Methods:

• Successfully processed HDPE and HDPE-V using a screw-assisted 3D printer.
• Compared shrinkage during printing between HDPE and HDPE-V.
• Analyzed mechanical anisotropy of 3D printed samples after an annealing process.

Main Results:

• HDPE-V demonstrated reduced shrinkage during the 3D printing process compared to regular HDPE.
• 3D printed HDPE-V exhibited improved dimensional stability.
• Post-printing annealing of HDPE-V led to a decrease in mechanical anisotropy.
• HDPE-V maintained dimensional integrity at elevated temperatures, enabling successful annealing.

Conclusions:

• HDPE-V are suitable for extrusion-based additive manufacturing, offering enhanced dimensional stability.
• The use of HDPE-V in 3D printing significantly mitigates common issues associated with polyethylene.
• The dynamic nature of HDPE-V allows for post-processing improvements, leading to more isotropic and dimensionally accurate parts.