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Enhancing the stability of urea-formaldehyde microcapsules for self-healing polymers through additive modulation
Sivashankari Rajasekaran1, Bao Huynh1, Scott C Bozeman2
1Department of Biomaterial and Biomedical Sciences, Oregon Health and Sciences University - School of Dentistry, Portland, OR 97201, United States of America.
This study enhances self-healing poly(urea-formaldehyde) (PUF) microcapsules using melamine and N,N-Dimethylacrylamide (DMAM). The modified microcapsules show improved durability and elasticity, maintaining high cell viability for biomedical applications like dental composites.
Area of Science:
- Materials Science
- Polymer Chemistry
- Biomaterials Engineering
Background:
- Self-healing poly(urea-formaldehyde) (PUF) microcapsules are widely used but face challenges in mechanical stability and formaldehyde toxicity.
- Enhancing PUF microcapsules is crucial for expanding their application in demanding fields like biomedical systems.
Purpose of the Study:
- To improve the thermomechanical stability and cytocompatibility of PUF microcapsules.
- To investigate the effects of incorporating melamine and N,N-Dimethylacrylamide (DMAM) into PUF microcapsules.
Main Methods:
- PUF microcapsules were synthesized with melamine (up to 10 wt%) and a blend of triethylene glycol dimethacrylate (TEGDMA) and DMAM (20 wt%).
- Characterization included morphology, mechanical, thermal, and biological property assessments.
- Formaldehyde release was quantified using the Purpald assay, and dental pulp stem cell (DPSC) viability was evaluated.
Main Results:
- Melamine incorporation increased shell roughness and stability, with 5 wt% showing optimal balance.
- DMAM significantly enhanced shell elasticity, reaching 57% with combined DMAM and melamine.
- Formaldehyde release increased with melamine, but DPSC viability remained high (≥95% direct exposure, ≥85% overall).
- Self-healing efficiency exceeded 82%, with DMAM systems showing a ~20% improvement.
Conclusions:
- Melamine and DMAM effectively enhance the durability and elasticity of PUF microcapsules.
- The modified microcapsules demonstrate excellent cytocompatibility, suitable for biomedical applications.
- These findings support the use of enhanced PUF microcapsules in self-healing dental composites.
