Montmorillonite nanoclays

The incorporation of unmodified and organically modified montmorillonite nanoclays (namely 15A and 30B) in chlorinated polyethylene (CPE) by the solution intercalation method and their influence on mechanical properties of the nanocomposites have been studied by Kar et al. [137]. The o-MMT-embedded nanocomposites show enhanced tensile strength and Young s modulus in comparison to the nanocomposites containing the unmodified nanoclay. They have shown from and XRD analyses that organically modified clay shows better dispersion in the CPE matrix. This has been further substantiated from FTIR analysis, which proves an interaction between the CPE matrix and the clay intercalates. 

Tables 4.28 and 4.29 show effect of a montmorillonite nanoclay employed as a masterbatch (PolyOne Nanoblend 1001) in polypropylene on polypropylene-based composite containing 50% (w/w) maple wood flour and on flexural strength and modulus of the WPC.

Tunc and Duman (2011) when the montmorillonite (nanoclays) content in chitosan films increased. Solid particles such as beeswax or montmorillonite probably reduce the diffusivity of the volatile compound because of increasing tortuosity and then delay of the aroma loss by the films. A significant increase of thymol release rate with the increase of the bran concentration was observed by Mastromatteo et al. (2009). So, in this case, incorporation of nanoparticles (spelt bran) had the opposite effect and was unfavorable for volatile compound retention. 

This work thus deals with the addition of different types of montmorillonite nanoclays, especially NaMMT, to thermosetting PF and PUF resins to study (1) the effect of the PF and PUF resins on the level of intercalation or exfoliation of the montmorillonite nanoclays (2) the influence of resin structure on intercalation and (3) the improvement in performance of the resin by analysing the performance of wood panels/composites bonded with PF/montmorillonite nanoclays. 

The thermal properties of the nanocomposites of diglycidyl ether of bisphenol A epoxy resin containing different montmorillonite nanoclays depends on the surface modifications of the nanoclays. Moreover, the addition of nanoclays improved the thermal properties of the nanocomposites, compared to the neat epoxy [59]. 

Abstract In this chapter, we report the findings of experimental investigations conducted on durability of glass fiber-reinforced polymer (GFRP) composites with and without the addition of montmorillonite nanoclay. First, neat and nanoclay-added epoxy systems were characterized to evaluate the extent of clay platelet exfoliation and dispersion of nanoclay. GFRP composite panels were then fabricated with neat/modified epoxy resin and exposed to six different conditions, i.e. hot-dry/wet, cold-dry/wet, ultraviolet radiation and alternate ultraviolet radiation-condensation. Room temperature condition samples were also used for baseline consideration. 

Dispersion of montmorillonite nanoclay into part A of epoxy resin... 

Therefore in order to understand the degree of exfoliation or intercalation. X-ray diffraction (XRD) analysis was carried out on multiple samples of pure 1-28E nanoclay, cured epoxy resin with and without nanoclay of 2 wt% loading as shown in Fig. 21.3. Intense peaks of 100% and 25% were observed at 26 = 3.8° and 26 = 19.7° for the pure montmorillonite nanoclay, similar to the standard montmorillonite-22A nanoclay available in the directory with a PDF 29-1499 in the Rigaku D/MAX 2200 X-ray diffractometer. However, for 2 wt% epoxy/nanoclay samples, the peak intensity was significantly reduced, and the interplanar spacing was increased, indicating that the platelets were... 

The decrease in weight gain for the nanophased composites can be attributed to the hybrid exfoliated and intercalated nanoclay platelets in polymer. Nanoclay platelets when exfoliated/dispersed well in the matrix provide the barrier to gas/liquid in a tortuous manner [12]. This can be attributed to the gas/moisture and radiation barrier properties of montmorillonite nanoclay, which is consistent with results reported by Woo et al. [35]. 

Static and Dynamic Mechanical Analysis of Coir Fiber/Montmorillonite Nanoclay-Filled Novolac/Epoxy Hybrid Nanocomposites... 

Fig. 2 The join visible Fi lK spectra of a unmodified and b modified montmorillonite nanoclay...

The viscoelastic and thermal properties of fully and partially cured DGEBA epoxy resin composites were smdied modified with montmorillonite nanoclay exposed to UV radiation. Samples were fabricated and cured to 80 % conversion (partially cured) based on isothermal cure kinetic smdies. Influence of 1-3 wt% loading of montmorillonite nanoclay on the cure behavior and development of physical properties of these composites were evaluated. Results of the smdy revealed that for optimization of modified epoxy composite properties, a different curing cycle was necessary due to interaction of different amounts of nanoclay and epoxy molecules. Addition of nanoclay increased the viscoelastic properties, storage modulus and activation energy of decomposition of partially cured samples evolved over exposure time, while fuUy cured samples degraded over the same period. 

Table 6.1 Organic modifiers for commercially available montmorillonite nanoclays...

Table 6.1 includes typical quaternary ammonium salts used as organic modifiers in commercial montmorillonite nanoclays, which are to be primarily dispersed in nonpolar matrices. Figure 6.5 shows that hydrotalcite platelets of nanodimensions present a much smaller degree of agglomeration than the MMT particles. 

Rashmi, Renukappa NM, Ranganathaiah C, Shivakumar KN (2011) Montmorillonite nanoclay filler effects on electrical conductivity, thermal and mechanical properties of epoxy-based nanocomposites. Polym Eng Sci 51 1827—1836... 

In case of immiscible polymer pairs the ternary mixture is more stable thermodynamically (their adsorption on the surface of solid particle is more preferred than that of a miscible polymer pair). This is the basis of the nanocompatibilization (i.e. compatibilization with the aid of nanoparticles). Performance fire retardant system of polypropylene (PP) and phosphorylated epoxy resin (PEP) was reported to improve when montmorillonite nanoclay was introduced. Without nanoclay the distribution of epoxy in PP matrix was inhomogenous, while homogeneous nanodispersion could be achieved after attachment of PEP to clay nanoparticles as interlayer. (8). 

Insights into montmorillonite nanoclay based ex situ nanocomposites from SEBS and modified SEES by small-angle X-ray scattering and modulated DSC studies. Macromolecules, 41, 6246-6253. 

Deyrail Y, Mighri F, Bousmina M, Kaliaguine S. Polyamide/polystyrene blend compatibilisation by montmorillonite nanoclay and its effect on macroporosity of gas diffusion layers for proton exchange membrane fuel cells. Fuel Cells 2007 7 447-52. 

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