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

Abstract

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.

Enhanced strain hardening in elongational viscosity for HDPE/crosslinked HDPE blend. II. Processability of thermoforming

“…The photopolymerization of styrene derivatives was carried out in a matrix of the solid polymer and was followed up to high monomer conversions by Fourier transform real‐time infrared (RTIR) spectroscopy,8,15–18 which was conducted on a Bio‐Rad FTS‐40 (Bio‐Rad Laboratories, Inc., Hercules, CA) with Win‐IR operating/analysis software. Polystyrene and poly(BzTD) were the most frequently used matrix polymers.…”

Síntese e fotoatividade de macroiniciadores baseados em tioxantona - estudo mecanístico e aplicações

“…A forma sigmóide da curva, na presença de ar, é atribuída a dois fatores 67,68 : período de indução inicial devido ao efeito inibidor do oxigênio na polimerização radicalar, e constância no final devido ao efeito gel, com a constante de velocidade diminuindo por restrições de mobilidade quando há maior concentração de polímero no meio. O tempo de irradiação aumenta.…”