The Surface Reactivity Of Vermiculite Towards Hexamethylene Diisocyanate (HMDI)

B. Siffert and H. Biava
Centre de Recherches sur la Physico-Chimie des Surfaces Solides, 24, Avenue du Président Kennedy, 68200 Mulhouse, France

Abstract: The reaction of hexamethylene diisocyanate with the surface of heat-activated vermiculite parallels the reactions with the oxides SiO2, Al2O3, MgO considered individually, which a number of authors have already described. The fixation ratio is about 5 molecules per 100 Å2 area. Nearly one half of the grafted molecules retain a “free” isocyanate function, which is requisite for a subsequent polyaddition of the processed mineral. The interaction with vermiculite occurs according to three principal processes; (i) formation of a surface urethane, (ii) formation of a surface carbamate, (iii) fixation by hydrogen bonds.

Clays and Clay Minerals; December 1976 v. 24; no. 6; p. 303-311; DOI: 10.1346/CCMN.1976.0240606
© 1976, The Clay Minerals Society
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