Tracking of Epoxy Hardening Reaction
by Use of Near Infrared (NIR) Spectroscopy



  • In the near-infrared region (4000-10000cm-1), since overtones and so forth are detected, spectroscopy in the region has an advantage over that in the IR range that it is easy to identify functional groups. For this reason, NIR spectroscopy is superior in the detection and identification of the epoxy, R-OH and NH groups and water, among other things, which are difficult with IR spectroscopy.
  • Unlike IR spectroscopy, glass can be used for the window pane in NIR spectroscopy. For this reason, NIR spectroscopy makes it possible to track reactions with the conditions set to be very close to those of actual products.
  • Curable resin systems: Tracking of the reactions of epoxy resin-compounded materials and adhesives, and determination of the curing rate and the end points
  • Materials in general: Determination of the amounts of the NH and OH groups, and identification of OH of water and alcoholic OH

Example of measurement Tracking of curing reaction of an epoxy-based adhesive

●NIR spectra of a mixture of a polymer having the epoxy group and a curing agent

Top: before reaction; bottom: after completion of curing

It is clearly seen that the peaks derived from the epoxy group and the curing agent have disappeared.

●Tracking of reaction of an epoxy-based adhesive

Top: epoxy group: bottom: curing agent

Initially, reaction with the curing agent proceeded quickly. After the curing agent had been consumed, the thermal polymerization reaction of the epoxy group proceeded.

Search Number 1017

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