Hydrolytic stability of methacrylamide in acidic aqueous solution

Area of Science:

• Dental materials science
• Polymer chemistry

Background:

• Self-etching primers are crucial in dental adhesion.
• Current primers often have limited shelf life due to hydrolytic instability.
• Methacrylate-based monomers are susceptible to hydrolysis.

Purpose of the Study:

• To evaluate the hydrolytic stability of N-methacryloyl glycine (NMGly) as a component in self-etching primers.
• To compare the stability of NMGly with 2-hydroxyethyl methacrylate (HEMA).
• To assess the potential for improved shelf life in dental primers.

Main Methods:

• Examined the hydrolytic stability of the amide group in NMGly.
• Compared the degradation of NMGly with the methacrylate HEMA in aqueous solutions.
• Investigated the impact of acidic conditions on monomer stability.

Main Results:

• Methacrylate monomers like HEMA undergo hydrolysis in acidic aqueous solutions, producing methacrylic acid (MA) and ethylene glycol (EG).
• The amide portion of NMGly exhibited greater hydrolytic stability than the ester portion of HEMA.
• Prolonged storage of conventional self-etching primers leads to alteration of functional methacrylates.

Conclusions:

• N-methacryloyl glycine (NMGly) offers enhanced hydrolytic stability compared to methacrylate-based monomers.
• NMGly shows promise as a more stable monomer for developing self-etching primers with extended shelf life.
• This finding could lead to more durable and reliable dental adhesive systems.