title: The influence of water on the intercalation of epoxy monomers in Na-montmorillonite.
abstract: The intercalation of a typical UV-curable epoxy monomer (CE) in unmodified montmorillonite and the effect of hydration on the intercalation reaction are studied. Montmorillonite in the sodium form was submitted to a controlled hydration/dehydration cycle and the water content was checked by TGA/XRD analyses. The structure of the hydrated Na+-montmorillonite was determined from the values of the basal spacings and from the water content of the hydrated form: a coordination of four water molecules per Na ion was found, corresponding to a minimum of energy calculated by molecular dynamics simulation. When dispersing the clay in the CE monomer, the anhydrous Na+-montmorillonite did not show any intercalation; on the contrary the hydrated form showed an increase of the basal spacing. A possible mechanism to explain the intercalation of the CE monomers is proposed.
authors.affiliation: Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, Politecnico di Torino, C.so Duca degli Abruzzi 24, Torino 10129, Italy. roberta.bongiovanni@polito.it
authors.forename: R
authors.initials: R
authors.lastname: Bongiovanni
authors.forename: D
authors.initials: D
authors.lastname: Mazza
authors.forename: S
authors.initials: S
authors.lastname: Ronchetti
authors.forename: E A
authors.initials: EA
authors.lastname: Turcato