UV-curable acrylate-based nanocomposites: effect of polyaniline additives on the curing performance

Composites of nanostructured polyaniline (PANI) conducting polymer in a polyester acrylate (PEA) formulation were made to provide conductive organic coatings. The effect of the presence and amount of PANI on the photocuring performance of the ultraviolet (UV)-curable acrylate system has been investigated employing real-time Fourier transform infrared spectroscopy as the main technique. Longer initial retardation of the radical polymerization and lower rates of cross-linking reactions were observed for dispersions containing PANI of higher than 3wt.%. The PEA/PANI samples were more affected than the neat PEA resin by the changes in UV light intensity and oxygen accessibility during UV curing. Samples with higher PANI content, of up to 10wt.%, were tested and could be partially cured even at UV light intensities as low as 2mW cm-2 when the oxygen replenishment into the system was inhibited. Thermal analysis revealed that the presence of PANI did not induce any significant change in Tg of the cured system, meaning that early decrease in mobility and vitrification is not the reason for lower ultimate conversion of the dispersions with higher PANI content compared with the neat PEA resin. Curing under strong UV lamps, of 1.5W cm-2 intensity, made it possible to reach high degrees of conversion on films with similar mechanical properties independent of the PANI content. Copyright (c) 2013 John Wiley & Sons, Ltd.