Real-time kinetic study of the polymerization activity of the photoinitiator system p-nitroaniline/N,N-dimethylaniline by real time IR spectroscopy

摘要

The polymerization process of different acrylic monomers photoinduced by the bimolecular system p-nitroaniline/N,N-dimethylaniline (pNA/DMA) under UV radiation was analyzed in situ by real-time IR spectroscopy. To this purpose an inexpensive, automatized and simple apparatus based on commercially available items easily assembled was developed. The conversion versus time curves recorded allow the polymerization rate and quantum yield to be determined at any stage of the reaction. The effect of various factors such as incident light-intensity, initiator and coinitiator concentration, functionality of the monomer on the kinetic of the polymerization process was analyzed. This technique allowed the evaluation of the dark polymerization developed just after a dose of UV radiation by being able to measure and control the polymerization degree. A comparison with alternative methods as Photo-DSC technique allows to evaluate the effect of the sample thickness on the kinetics of a photoinitiated acrylate polymerization. References: 24