Nanocomposites cloisite

FIGURE 9.31 Glass transition temperature versus clay content for an intercalated vinyl ester nanocomposite (Cloisite lOA), a microcomposite (vinyl monomCT clay), and neat resin. (From Ref. 95, copyright 2002, John Wiley Sons, Inc., with pamission.)... 

The exact same process with the same equipment that was employed to produce the nylon 6 nanocomposites was employed with the amorphous polyamide. The same procedure as outlined above with the nylon 6 nanocomposites was used to characterize the amorphous polyamide nanocomposites. Cloisite 30B and the organomontmorillonite prepared with trimethyl hydrogenated tallow quat demonstrated excellent exfoliation. Cloisite 20A was not as effective in exfoliation. The mechanical performance of the montmorillonite exchanged with trimethyl hydrogenated tallow quat had the superior Young s modulus. 

Maiti and Bhowmick reported exciting results that a polar matrix like fluoroelastomer (Viton B-50) was able to exfoliate unmodified clay (Cloisite NA ) as well as the modified one (Cloisite 20A) [93]. They studied morphology, mechanical, dynamic mechanical and swelling properties of fluoroelastomer nanocomposites. The unmodified-clay-filled systems showed better properties than the modified ones (Table 2.3). 

FIGURE 2.14 Tapping mode phase morphology of the nanocomposites (a) poly[styrene-(ethylene-co-butylene)-styrene] (SFBS)-Cloisite 20A and (b) its 3D image. (From Ganguly, A., Sarkar, M.D., and Bhowmick, A.K., J. Polym. ScL, Part B Polym. Phys., 45, 52, 2006. Courtesy of Wiley InterScience.)... 

Incorporation of modified clays into thermosetting resins, and particularly in epoxy35 or unsaturated polyester resins, in order to improve thermal stability or flame retardancy, has been reported.36 A thermogravimetric study of polyester-clay nanocomposites has shown that addition of nanoclays lowers the decomposition temperature and thermal stability of a standard resin up to 600°C. But, above this temperature, the trend is reversed in a region where a charring residue is formed. Char formation seems not as important as compared with other polymer-clay nanocomposite structures. Nazare et al.37 have studied the combination of APP and ammonium-modified MMT (Cloisite 10A, 15A, 25A, and 30B). The diluent used for polyester resin was methyl methacrylate (MMA). The... 

Figure 4.14. Thermogravimetric analysis of EVA nanocomposites filled with 3 wt% Cloisite 30B and either 0,0.5 or 1.0 wt% purified MWNTs under air flow at 20 K/min (unfilled EVA matrix is shown for sake of comparison). Reprinted with permission from ref (66).

A series of five nanocomposite elastomer systems were prepared for this study incorporating 0, 1, 2, 4 and 8% (on total resin mass) of the organically modified montmorillonite clay Cloisite 6A. The appropriate level of Cloisite was dispersed in a starting resin blend of OH terminated PDMS (M -77,000 and Mn -550 g mol in a 3 1 ratio) by a combination of mechanical mixing and ultrasonic processing to give a nano-dispersion of clay platelets. The blend was subsequently crosslinked with a stoichiometric level of tetrapropoxysilane (TPOS) in the presence of 5% diphenylmethylsilanol (DPMS) chain terminator and 5% tin(II) 2-ethylhexanoate catalyst, cured in an open mould at 65°C for twenty minutes, then removed from the mould and post cured for a further fifteen hours at 65°C to give an elastomeric mat. 

Figure 3. BDS spectra of nanocomposite systems at 40°C. Solid symbols represent real permittivity and hollow symbols represent imaginary permittivity. Squares, circles, up-triangles, down-triangles and diamonds represent levels of 0, 2, 4 and 8% Cloisite respectively.

Mirzataheri M, Mahdavian A, Atai M (2009) Nanocomposite particles with core-shell morphology IV an efficient approach to the encapsulation of Cloisite 30B by poly (styrene-co-butyl acrylate) and preparation of its nanocomposite latex via miniemulsion polymerization. Colloid Polym Sd 287 725-732... 

Xu et al. heterocoagulated cationic PMMA latex particles of an estimated 150-200 nm in diameter with various clays, Montmorillonite (GelWhite GP and Cloisite Na+) and (fluoro)hectorites (Laponite RD, RDS, B, S, JS), having plate dimensions between 25 and 600 nm. No details on the stable colloidal armored structures were reported. Mass coagulation was induced in order to obtain a nanocomposite bulk material, which was further analyzed [23]. Chen et al. [24] added Ti02 and SiOi/TiOi nanoparticles with a positive surface charge at a very low pH of 0-2 to both anionic and cationic latexes based on PMMA. A bulk nanocomposite blend was analyzed. 

Natural montroriUonite and organically modified MMT with methyl tallow bis-2-hydroxyethyl ammonium cations located in the silicate gallery (Cloisite 30B) were evaluted in starch-based nanocomposite [232]. It was observed that the TPS/ Cloisite Na-t nanocomposites showed higher tensile strength and thermal stability, better barrier properties to water vapor than the TPS/Cloisite 30B nanocomposites, as well as the pristine TPS, due to the formation of the intercalated nanostructure. Perez et al. [233] compared three different clays (Cloisite Na+, Cloisite 30B and Cloisite 10A) and found the best properties were achieved with Cloisite lOA due to their greatest compatibility with the matrix. 

FIGURE 6 The RHR versus time for PP, PP/MWCNT and PP/MMT (Cloisite 20A) nanocomposites obtained by cone calorimeter at the incident heat flux of 35 kW m. ... 

The processes of the combustion are studied for the number of a polymeric nanocomposites based on the layered silicates such as ttylon-6.6 with 5 wt% of Cloisite 15A - montmorillonite being modified with the dimethyldialkylammonium (alkyls studied CIS, C16, C14), maleinated polypropylene and polyethylene, both (1.5%) with 10 wt% Cloisite 15 A. The general trend is two times reduction of the speed of the heat release. The decrease in the period of the flame induction is repotted for all nanocomposites in comparison with the initial polymers [54]. 

A new polymer-inorganic nanocomposite SPEEK membrane filled with Cloisite 15A clay by introducing 2,4,6-triaminopyrimidine (TAP) as the compatibilizer for DMFC applications has been successfully prepared. The organoclay Cloisite is a material prepared from MMT and the cation ditallow. Tallow is a mixture of octa-decyl, hexadecyl, and tetradecyl, wherein octadecyl is the major component (>60%). Cloisite is a very promising additive in nanocomposite membranes, since it is already being organically modified from the natural MMT, which is expected to enhance the compatibility with organic polymers (Cervantes-Uc et al. 2007). 

It can be concluded that TAP was successfully incorporated into the SPEEK/ Cloisite 15A matrix to improve the compatibility between SPEEK and Cloisite 15A and thus to enhance the homogeneity of SPEEK/Cloisitel5A/TAP nanocomposite... 

Jaafar, J., Ismail, A.F and Matsuura, T. 2009. Preparation and barrier properties of SPEEK/ Cloisite 15A /TAP nanocomposite membrane for DMEC application. 

The effect of compatibilizer like styrene-ethylene/butylene-styrene triblock copolymer grafted with 1.84 wt% of maleic anhydride (SEBS-g-MA) on the tribological behavior of clay-polyamide-66 nanocomposites is also reported [111]. The wear volume increases and the coefficient of friction decreases almost linearly with the rise in load (Figure 9.45). However, the wear volume and the coefficient of friction are low for SEBS-g-MA com-patibilized clay-polyamide hybrid system. The wear volume is high for alkyl-ammonium modified clay (Cloisite - 30B). 

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