Monitoring the polymerization of a diglycidyl ether bisphenol-A/2,2'-dimethyl-4,4'-methylenebis (cyclohexylamine) matrix with a Fourier transform infrared optical fibre sensor

An optical fibre sensor (OFS) for the online monitoring of the polymerization reaction is described in this paper. The sensor, based on Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC) analysis, was used to study the reaction between diglycidyl ether bisphenol-A (DGEBA) and 2,20-dimethyl-4,40-methylenebis(cyclohexylamine) (DMMB-CHA). Changes in concentrations of reactants and products were monitored over the curing period at different temperatures by the FT-IR technique, and from DSC runs the variation in the enthalpy of reaction over time for different curing temperatures was determined. Plots of fractional conversions versus time from the two methods were produced and compared. An attempt to deduce glass transition temperatures from the fractional conversion curves produced by FT-IR is also described. This involved the use of the fitting polynomial calculated from the DSC results. As a result, a sensor designed for embedding into a system curing at elevated temperature was constructed and tested.