Multi-point monitoring of cross-linking reactions

Research output: Contribution to journalArticlepeer-review


  • Venkata Rajanikanth Machavaram
  • Sebastian Hellmann
  • Francisco Nieves Bogonez

Colleges, School and Institutes

External organisations

  • School of Metallurgy and Materials; University of Birmingham; Edgbaston Birmingham B15 2TT United Kingdom
  • School of Electronics Engineering VIT University, Vellore, Tamil Nadu, India
  • Department of Chemistry and Chemical Engineering, Minjiang University, Fuzhou, People's Republic of China


The feasibility of deploying optical fiber sensors to obtain qualitative and quantitative information on the cross-linking characteristics of thermosetting resin systems has been demonstrated by a number of researchers. This article is concerned with the demonstration of a low-cost fiber-optic Fresnel sensor system for monitoring the cross-linking reactions at multiple locations. Cross-linking reactions can be influenced by a number of parameters including the stoichiometry of the resin and hardener, and the heat-transfer rates in and out of the preform as a function of the cross-section of the preform. In situations where there is a variation in the thickness of the preform or when large components are processed, a facility to monitor the cross-linking reactions at multiple locations will be valuable because the rate and extent of the cross-linking can be inferred. In this article, six Fresnel sensors were immersed in individual vials containing an epoxy/amine resin system and processed (cross-linked) in an air-circulating oven. One additional vial with a Fresnel sensor immersed in the neat epoxy resin (no hardener) was co-located in the oven to enable the effect of temperature to be monitored. The feasibility of using the multiplexed Fresnel sensors for cure monitoring was demonstrated successfully. The sensors in the post-cross-linked samples were used to study the effects of heating and cooling cycles. The feasibility of detecting the glass transition temperature using the Fresnel sensor is discussed along with the factors that give rise to variability in the output Fresnel signals. © 2014 The Authors. Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41088.


Original languageEnglish
Article number41088
JournalJournal of Applied Polymer Science
Issue number22
Early online date3 Jul 2014
Publication statusPublished - 15 Nov 2014


  • cross-linking, resins, manufacturing, optical properties, thermosets