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The Sodium Montmorillonite (Na-MMT) is not susceptible to polymer due to its organophilic character and low basal spacing. The primary objective of this study was to improve Na-MMT platelets separation by organically modifying it with cation and anion exchanges using Cetyl trimethyl ammonium bromide (CTAB) and Sodium dodecyl sulfate (SDS) respectively. Basal spacing, presence of functional groups, Zetapotential with particle size analysis and thermal stability of the Organomodified Na-MMT (OMMT) were characterized using XRD, FTIR, zeta-potential analyzer and TGA respectively. The basal spacing of CTAB modified OMMT increased to 19.5 Å from 11.0 Å which corresponds to the basal spacing of Na-MMT. The SDS modified OMMT did not show any increase in the basal spacing. FTIR spectra of CTAB modified Na-MMT illustrated the attachment of CTAB functional groups to Na-MMT, while the same was absent in the case of SDS modified Na-MMT. The zeta-potential of Na-MMT shifted from -24.88 mV to 15.66 mV in the case of CTAB modified Na-MMT and 12.49 mV for SDS modified Na-MMT, indicating a greater surface potential of the modified nanoclay. The TGA showed greater weight loss for CTAB modified Na-MMT than that for Na-MMT, indicating the effective Na + ion exchange with alkyl amines.

This research concerns moisture absorption through nanoclay/vinylester composites in artificial seawater medium and the resulting properties of degradation. Cloisite 15A, an organomodified nanoclay, and Cloisite Na, a naturally occurring nanoclay, were studied to examine the influence of organomodification on the moisture ingress behavior of the nanocomposites processed by using ultrasonication and twin-screw extrusion. Although X-ray diffraction and transmission electron microscopy analysis revealed exfoliation of Cloisite 15A in vinylester, Cloisite Na was only intercalated. Moisture diffusivity decreased by 72% due to the addition of 5 wt% of Cloisite 15A to vinylester. However, the same increased in the case of the addition of Cloisite Na, suggesting a positive influence of the organomodification on the moisture barrier properties. Although Fick's Law of Diffusion showed deviation from the experimental data in the nonlinear region of moisture absorption as a function of duration of exposure, the Langmuir Model was in better agreement with the experimental data in the entire range. (Cloisite 15A)/vinylester showed lower levels of microhardness deterioration due to moisture absorption than that of (Cloisite Na)/vinylester. J. VINYL ADDIT. TECHNOL.,

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