A simple, inexpensive, real-time interferometric cure monitoring system for optically cured polymers

• Published in: Journal of applied polymer science 2013-09, Vol.129 (5), p.2653-2662
• Main Authors: Schwerzel, Robert E., Jariwala, Amit S., Rosen, David W.
• Format: Article
• Language: English
• Subjects: Applied sciences; crosslinking; Exact sciences and technology; kinetics; Materials science; optical properties; photopolymerization; photorefractive effects; Physicochemistry of polymers; Polymerization; Polymers; Polymers and radiations
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.38993

Optically cured polymers play a crucial role in many commercial applications, ranging from UV‐cured inks, coatings, and dental fillings to the optical fabrication of three‐dimensional prototypes by means of stereolithography. However, our understanding of the detailed processes that occur in the curing of these materials is often limited by the practical difficulty of observing the cure process in real time, under “real‐world” conditions. This article reports the simple implementation of a free‐space Mach‐Zehnder interferometer that can be constructed inexpensively from readily available components, and demonstrates its utility in monitoring the UV curing of a typical acrylate photopolymer system in real time. In particular, it is shown that this system can sensitively track the induction period, the light‐induced photopolymerization reaction, and the subsequent dark reaction that continues after the irradiation has been halted. This Interferometric Cure Monitor, or “ICM,” thus provides a valuable addition to other analytical methods, both for improving the quality control of existing commercial processes and for aiding the development of improved photopolymer formulations. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013