کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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613743 | 880727 | 2006 | 5 صفحه PDF | دانلود رایگان |
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.
XRD spectra of sodium montmorillonite dispersions in an epoxy monomer (5% w/w): when the clay is anhydrous (d-spacing = 9.6 Å), no intercalation occurs (blue curve); the hydrated form of the montmorillonite (d-spacing = 12.1 Å) shows an increase in basal spacing from 12.1 to 14.7 Å (the wide halo derives from the amorphous scattering of the liquid monomer).Figure optionsDownload as PowerPoint slide
Journal: Journal of Colloid and Interface Science - Volume 296, Issue 2, 15 April 2006, Pages 515–519