Photopolymerization monitoring of ceramic stereolithography resins by FTIR methods

Abstract

Curing kinetics of UV photocurable acrylate monomer-based ceramic resins were studied using a Fourier Transform Infrared (FTIR) spectroscopy instrument with an internally-mounted UV-curing source, providing real-time quantification of the acrylate double bond conversion with respect to increasing UV dose. The results show that this Real Time FTIR experiment (RTFTIR) provides a simple but valuable means of investigating average photopolymerization kinetics and final conversion in a thin layer of highly loaded ceramic suspension. This RTFTIR technique showed complete agreement with differential photo-calorimetry (photoDSC) experiments performed on the same thickness and amount highly loaded ceramic suspension.

FTIR was also used to investigate the curing behavior inside sublayers of the same ceramic suspension. Curing kinetics and final conversion were monitored in these layers, with higher conversion and faster kinetics being observed near the exposed surface. Due to the scattering and absorption effects within the uppermost layers, photopolymerization rate and percent conversion declined as a function of depth from the surface.