Effect of thermal aging on a urethane acrylate-based 3D printing resin incorporated with antibacterial quaternary ammonium methacrylate

Area of Science:

• Materials Science
• Biomaterials Engineering
• Polymer Chemistry

Background:

• Urethane acrylate (UA)-based resins are utilized in 3D printing for various applications.
• Incorporating functional monomers like dimethylaminohexadecyl methacrylate (DMAHDM) can impart desirable properties such as antimicrobial activity.
• Understanding the effects of aging, particularly thermal aging, is crucial for assessing the long-term performance and safety of 3D printed materials.

Purpose of the Study:

• To investigate the impact of varying concentrations of DMAHDM on the properties of UA-based 3D printing resins.
• To evaluate the effects of thermal aging (5°C and 55°C for up to 5000 cycles) on these modified resins.
• To assess changes in mechanical properties, biocompatibility, and antibacterial effectiveness.

Main Methods:

• DMAHDM was synthesized and incorporated into UA resin at concentrations of 0.25, 0.5, 0.75, and 1 wt%.
• 3D printed specimens underwent thermal cycling, followed by evaluations of degree of conversion (DC), color stability, antibacterial activity, cell viability, flexural strength, and Vickers hardness.
• Statistical analysis using two-way ANOVA was performed to determine significance (α=0.05).

Main Results:

• DMAHDM addition increased DC and enhanced antibacterial effectiveness, particularly at 0.75 wt% and 1 wt%.
• Flexural strength decreased with increasing DMAHDM concentration and thermal aging, while Vickers hardness significantly increased.
• Prolonged thermal aging led to noticeable color changes and increased cytotoxicity, indicating potential biocompatibility issues.

Conclusions:

• DMAHDM concentration and thermal aging significantly alter the properties of UA-based 3D printing resins.
• While DMAHDM enhances antibacterial properties and hardness, it compromises flexural strength at higher concentrations and after aging.
• Thermal aging negatively impacts mechanical strength and biocompatibility, highlighting the need for careful material selection and processing for long-term applications.