Background:
Nanoclays incorporated in dental resins have been previously investigated.
However, limited reports are associated with nanoclays that exhibit high functionality.
Objective:
The aim of this study was the targeted synthesis and characterization of organomodified
nanoclays with methacrylic groups suitable for incorporation in dental nanocomposite resins.
Methods:
Quaternary ammonium methacrylates were synthesized and characterized by means of
proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Consequently, they
were inserted into the interlayer space of nanoclay through a cation exchange reaction, while silane
was also used for simultaneous surface modification. The produced organomodified nanoclays were
characterized by means of X-ray diffraction, Fourier-transform infrared spectroscopy and thermogravimetric
analysis.
Results:
Fourier-transform infrared spectra confirmed the successful synthesis of the quaternary
ammonium methacrylates. X-ray diffraction analysis showed that organoclays exhibited higher d001-
values (up to 1.78 nm) compared to raw nanoclay (1.37 nm), indicating an accomplished intercalation
in each case. X-ray diffraction spectra mainly disclosed the presence of methacrylic functional
groups in all nanoclays. Thermogravimetric analysis curves verified the different thermal stability of
organoclays due to the diversity of their organic modifiers.
Conclusion:
The experimental results showed that nanoclay was successfully modified with ammonium
methacrylates and silane. Τhe combination of X-ray diffraction and thermogravimetric analysis
data revealed a high degree of intercalation and methacrylated organic loading as well. These phenomena
may favor a good dispersion and high polymerization degree of nanoclays with dental resin
monomers, rendering them potentially useful materials for the development of advanced dental
nanocomposites resins.
