Premium
Interfacial chemistry of epoxy adhesives on hydrated cement paste
Author(s) -
Djouani Fatma,
Connan Carole,
Chehimi Mohamed M.,
Benzarti Karim
Publication year - 2008
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.2783
Subject(s) - epoxy , portlandite , diethylenetriamine , adhesive , differential scanning calorimetry , x ray photoelectron spectroscopy , materials science , bisphenol a , polymer , composite material , cement , glass transition , chemical engineering , polymer chemistry , portland cement , layer (electronics) , engineering , physics , thermodynamics
Abstract Epoxy resins [diglycidylether of bisphenol A, (DGEBA)] are the main adhesives used in civil engineering for the repair of damaged concrete structures (bridges, walls) or for assembly applications. Their interfacial molecular interactions with cement‐type substrates are thus of prime importance and require surface‐ and interface‐sensitive characterisation tools. In this context, we report an XPS, FTIR and differential scanning calorimeter (DSC) study of the interfacial chemistry of stoichiometric and nonstoichiometric epoxy mixtures [i.e. DGEBA resin and diethylenetriamine hardener (DETA)] coated on the surface of hardened‐cement pastes. XPS highlights the cross‐linking of the epoxy resin by the hardener and allows the detection of subtle mineral‐DETA hydrogen bonding. These specific interactions are confirmed by examination of the OH‐stretching frequency shifts in the FTIR spectra and concern essentially portlandite, one of the constitutive hydrates of cement paste. Additionally, it was found that interactions between the cross‐linked epoxy resin and the underlying‐mineral substrate induce an increase in the glass transition temperature ( T g ) of the polymer adhesive from 48 to 66 °C. Copyright © 2008 John Wiley & Sons, Ltd.