Photopolymerization of clay/polyurethane nanocomposites induced by an intercalated photoinitiator through sol–gel modification

An organic silane photoinitiator (1173IPS) was synthesized through the reaction of (3-Isocyanatopropyl)triethoxysilane (IPS) and 2-hydroxy-2-methyl-1-phenylpropane-1-one (1173). The objective of this work was to intercalate photoinitiator 1173IPS into a montmorillonite (MMT) through sol–gel reaction of cationic triethoxysilanepropylamineformylethyl trimethyl ammonium iodide (APS) and 1173IPS. The modified clay was then mixed with urethaneacylate oligomer (CN962) and 1,6-hexanediol diacrylate (HDDA) to form polyurethane–nanoclay composites by photopolymerization. Real-time FTIR (RTIR) results showed the system had almost the same final conversion but different polymerization rates with different ratios of APS/1173IPS modified clay. XRD and TEM results showed that the modified clay was exfoliated and dispersed in parallel alignments as multilayers in the organic matrix.