ISSN:
1572-8935
Keywords:
Isothermal cure
;
Epoxy-novolac molding compound
;
Differential scanning calorimetry
;
Infrared spectroscopy
;
Dielectrometry
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The isothermal cure of an epoxy-novolac molding compound was studied by means of Fourier-transform infrared spectroscopy (FTIR) and dielectrometry (DE). Results obtained were compared with previous differential scanning calorimetric (DSC) observations. The behavior of epoxide conversion (αFTIR) measured via FTIR was found similar to (but not exactly coinciding with) the extent of cure (αDSC) determined previously by means of DSC. As for the DE analysis, directly measurable properties such as permittivity (ɛ′) and loss factor (ɛ″) varied in a complicated manner during the course of cure, showing strong dependence on both temperature and frequency. Other dielectric parameters (such as ionic conductivity, relaxed permittivity, and characteristic relaxation time) previously suggested in the literature as suitable for cure monitoring purposes were found difficult to determine within the limited frequency range (100 to 104 Hz) here. With some arbitrariness, the relative drop in logɛ″ (at 100 Hz) was taken as an index (αDE) for the extent of cure. It was observed that αDE behaves in a manner similar to αFTIR and αDSC Comments on the application of these three techniques in the characterization of thermosetting systems were given.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01374556
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