Dielectric monitoring of epoxy cure

✍ Scribed by G. Levita; A. Livi; P. A. Rolla; C. Culicchi

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 534 KB
• Volume: 34
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19961130)34:16<2731::aid-polb6>3.0.co;2-s

✦ Synopsis

The cure process of mixtures of a DGEBA-type epoxy resin and ethylenediamine, in different molar ratios, was investigated by dielectrometry in a wide frequency range, 103-2 10'' Hz, at three temperatures, 25,60, and 70°C. Two relaxation processes were found whose relevant parameters were obtained by a proper fit procedure. A deeper knowledge and a quantitative description of the observed effects was achieved by analyzing the change of dielectric data caused by the chemical reaction. The change of the dielectric strength of both processes, as well as of other dielectric parameters, reflect the chemical modifications of the system; the permittivity, both static and at microwave frequencies, was linearly related to the conversion. These results support the interpretative model based on the disappearance of dipoles, and confirm the permittivity as a valuable quantity to monitor the kinetics of the reaction.