In-situ synthesis of exfoliated nanocomposites by photopolymerization using a novel montmorillonite-anchored initiator

A novel quaternized ammonium photoinitiator (BDMBAC) was synthesized by facile neutralization of BDMB and hydrochloric acid, then ion-exchanged with montmorillonite (MMT). An ordered swollen structure of the intercalated montmorillonite was evidenced by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermo gravimetric analysis (TGA). The BDMBAC molecules were anchored in the interlayer space of montmorillonite. These BMDBAC-modified montmorillonite were then dispersed in urethane acrylate oligomers and in-situ photopolymerized yielding exfoliated PUA–montmorillonite nanocomposites. The photopolymerization kinetics was monitored by real-time infrared spectroscopy. X-ray diffraction and transmission electron microscopy (TEM) revealed that the modified montmorillonite layers were uniformly dispersed in the PUA matrix. Thermal properties of the resultant nanocomposites were studied by TGA.