Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Interfacial chemistry of epoxy adhesives on hydrated cement paste
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, the authors 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 (Tg) of the polymer adhesive from 48 to 66 deg C.
Interfacial chemistry of epoxy adhesives on hydrated cement paste
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, the authors 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 (Tg) of the polymer adhesive from 48 to 66 deg C.
Interfacial chemistry of epoxy adhesives on hydrated cement paste
Grenzflächenchemie von Epoxidharzklebern auf hydrierten Zementpasten
Djouani, Fatma (Autor:in) / Connan, Carole (Autor:in) / Chehimi, Mohamed M. (Autor:in) / Benzarti, Karim (Autor:in)
2008
5 Seiten, 5 Bilder, 13 Quellen
Aufsatz (Konferenz)
Englisch
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