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Network formation in an epoxy system: A kinetics, viscometric and viscoelastic study
Author(s) -
Feve Michel
Publication year - 1989
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19890300110
Subject(s) - viscoelasticity , differential scanning calorimetry , viscometer , glass transition , kinetics , isothermal process , curing (chemistry) , gel point , epoxy , thermodynamics , elasticity (physics) , materials science , dynamic mechanical analysis , polymer chemistry , rheometry , viscosity , natural rubber , composite material , rheology , polymer , physics , quantum mechanics
A purely aliphatic diepoxy‐diamine system has been used. It is well suited for a gelation study because the chemistry is very simple and the glass transition temperature of the obtained rubber is more than 50 degrees lower than the curing temperature. The kinetics equation, established using isothermal differential scanning calorimetry (DSC) runs, agree well with that suggested by R.J.J. WILLIAMS et al. (1984). The viscoelastic behaviour, monitored by dynamic mechanical analysis, exhibits three successive zones: viscous liquid, viscoelastic material, elastic solid. Gelation occurs in the second one, the duration of which is very short. At the gel point, we observe the behaviour described by CHAMBON & WINTER (1985): tgδ is independent of the frequency;η* and G', respectively, are proportional to ω −1/2 and ω 1/2 . The high values of viscosity displayed by the viscometer are wrong and the measured torque derives from the elasticity of the material.