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Comparison of four methods for monitoring the kinetics of curing of a phenolic resin
Author(s) -
Malkin A.Ya.,
Gorbunova I.Yu.,
Kerber M.L.
Publication year - 2005
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.20234
Subject(s) - curing (chemistry) , materials science , differential scanning calorimetry , kinetics , viscometer , thermodynamics , extrapolation , viscosity , composite material , polymer chemistry , mathematics , physics , quantum mechanics , mathematical analysis
The kinetics of curing of several phenolic resin compounds were studied with the use of four techniques: viscometry, infrared spectroscopy (IR), differential scanning calorimetry (DSC), and thermomechanical analysis. The objective was to compare the effectiveness of these methods. It was found that the viscosity increase during oligomer curing can be described by an exponential function, and that the rate of viscosity increase can be described in terms of a “viscometric” kinetic constant, k η . The gel‐time, t *, was found by extrapolation of the time dependence of the reciprocal viscosity. The product ( t * k η ) appears to be constant for all temperatures. It was concluded that each experimental technique reflects a different kinetic process, and it is not possible to correlate the results of one technique with those of another. The degree of conversion at the gel point, β*, depends on temperature, and it is thought that this is due to the heterogeneous nature of curing. The glass temperature (as determined from the maximum in the loss tangent) is related to the degree of curing by the DiBenedetto equation, which can be used to determine the degree of conversion during the final stages of the reaction. POLYM. ENG. SCI. 45:95–102, 2005. © 2004 Society of Plastics Engineers