Moisture diffusion through nanoclay/vinylester processed using twin‐screw extrusion

Abstract

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.,

Physical and mechanical properties of linear low‐density polyethylene/cycloolefin copolymer/layered silicate nanocomposite

“…The minimum intercalated–exfoliated structure observed with C10A clay and the numerous tactoids observed in the TEM images can promote the formation of microcavities or microvoids between clay and polymer matrix that could increase the gas diffusion through the polymer matrix. This is in agreement with the results obtained by other authors who have found that clay tactoids or aggregates increase the water diffusion of polymer nanocomposites.…”

Moisture Absorption of Carbon/Epoxy Nanocomposites

“…Polymers readily absorb and retain moisture, which in turn plasticizes the resin, causes swelling and may induce considerable residual stresses and delamination in the material [2,14,15]. These microstructural changes often alter the physical and mechanical properties of the composites, and therefore adversely affect their service life [14,[16][17][18][19][20].…”

Dispersion study of clay nanoparticles in vinylester resin

“…David et al (2012) observed more hydrophobic behavior, higher barrier property and lower chain mobility for organically modified Cloisite 15A compared to the normal MMT . The compatibility of Cloisite 15A with vinylester resin is found to be significant as remarkable improvement is observed in the thermal and mechanical properties . Hence, Cloisite 15A is chosen as a reinforcement with vinylester being used as a polymer matrix for manufacturing of nanocomposite.…”