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Curing of dicyandiamide epoxy resins accelerated with substituted ureas
Author(s) -
Poisson N.,
Maazouz A.,
Sautereau H.,
Taha M.,
Gambert X.
Publication year - 1998
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19980919)69:12<2487::aid-app20>3.0.co;2-t
Subject(s) - epoxy , differential scanning calorimetry , bisphenol a , curing (chemistry) , materials science , polymer chemistry , thermosetting polymer , fourier transform infrared spectroscopy , amine gas treating , composite material , chemical engineering , chemistry , organic chemistry , physics , thermodynamics , engineering
An epoxy resin based on bisphenol‐A‐diglycidylether (DGEBA) was cured with dicyandiamide (DDA) and different substituted ureas (Urones) as accelerators. Differential scanning calorimetry, size exclusion chromatography, and Fourier transform infrared (IR) analysis indicated complex reaction mechanisms. The DDA granulometry seemed not to be a predominant parameter, but its content clearly influences T g of the network. The maximum T g value was found for an amine‐to‐epoxy molar ratio of 0.6. IR spectra revealed the appearance of oxazolidone rings, which are the first product of epoxy reactions. Urone accelerators also acted as homopolymerization initiators; they modified the epoxy conversion at gelation and changed of the structure of the obtained network. Influence of uron nature and content on reaction rates were also studied. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 69: 2487–2497, 1998