Chitosan-clay compositions

Chenu C, Pons C H, Robert M (1987), Chitosan/clay composites , Proceedings of the international clay conference, Denver, CO. 

Figure 4.6 shows the XRD patterns of pure clay (sodium montmoril-lonite), neat chitosan, chitosan/clay, chitosan /CNTs and chitosan/ CNT-clay composite. Neat chitosan film shows weak crystalline... 

Figure 4.5. (a) Tensile strength of chitosan/clay nanocomposite as a function of clay content (b) tensile strength of chitosan/CNTs nanocomposite as a function of CNT content (c) stress-strain behavior for neat chitosan, chitosan/0.4% CNTs, chitosan/3% clay, and chitosan/3%clay/0.4% CNTs composites (d) tensile strength of chitosan/clay/CNTs nanocomposite as a function of clay content. Reprinted with permission from ref (42). 

Schematic illustration of clay and CNTs morphology in chitosan nanocomposites is shown in Figure 4.8. In the composites based on chitosan/CNTs containing 0.4 wt % CNTs, nanotubes can be well dispersed in chitosan, but no filler network could be formed due to its low concentration (Figure 4.8a). In the composites based on chitosan/clay containing 3 wt % clay, formation of 2D clay platelets network is possible (Figure 4.8b). In chitosan/clay-CNTs ternary nanocomposites, ID CNTs are confined in 2D clay platelets network, which results in a much jammed and conjugated 3D clay-CNTs network (Figure 4.8c). The interactions and networks in the system can be divided into (1) clay-clay network, (2) clay-CNTs network, (3) CNTs-polymer-clay bridging, (4) polymer-polymer network. The formation of different networks and interactions could be the main reason for the observed synergistic reinforcement of CNT and clay...

Figure 4.18. SEM images of the char of chitosan nanocomposites after TGA tests (a) chitosan/3% clay (b) chitosan/3% CNT (c) chitosan/2% clay/1% CNT composites. Reprinted with permission from ref (69).

U.S. 2002/0016276 02/2002 Spendel/Procter Gamble Yarn strength-enhancing agents suitable for laundry and/or fabric care compositions. The additives that improve yarn strength can include polysaccharides, clays, starches, chitosans, and mixtures thereof... 

Bora, M. Ganguli, J. N. Dutta, D. K (2000). Thermal and spectroscopic studies on the decomposition of [Ni di(2-aminoethyl)amine 2]- and [Ni(2,2" 6",2"-terpyridine)2]-Montmorillonite intercalated composites Thermochimica Acta. Vol. 346, p.169-175. Ghang, M. Y. Juang, R. S. (2004). Adsorption of tannic acid, humic acid and dyes from water using the composite of chitosan and activated clay. Journal of Colloid and Interface Science. Vol. 278, pp.18-25. 

Montmorillonite, silicate, aluminosilicate, titanosilicate, calcium phosphate, zirconium phosphate, metal oxides, and heteropolyacids composites with Nation exhibit in general a modest barrier effect to methanol permeation (F, > 0.1), with a couple of exceptions aCloisite lOA composite [62] with 0.013 < F, < 0.065, and a chitosan-functionalized montmorillonite composite [71] with 0.028 < F < 0.050, in both cases for clay contents between 1 and 10 wt%. 

Chang, M.Y. and Juang, R.S. 2004. Adsorption of tannic acid, humic acid, and dyes from water using the composite of chitosan and activated clay. J. Coll. Interface Sci. 278 18-25. 

Sumita M, Tsukumo Y, Miyasaka K et al (1983) Tensile yield stress of polypropylene composites filled with ultrafine particles. J Mater Sci 18 1758—1764 Thellen C, Orroth C, Froio D et al (2005) Influence of montmorillonite layered silicate on plasticized poly(l-lactide) blown films. Polymer 46 1716-11727 Uyama H, Kuwabara M, Tsujimoto T et al (2003) Green nanocomposites from renewable resources plant oil-clay hybrid materials. Chem Mater 15 2492-2494 Wang SF, Shen L, Zhang WD et al (2005a) Preparation and mechanical properties of chitosan/ carhon nanotuhes composites. Biomactomolecules 6 3067—3072... 

C5 ras VP, Manfredi LB, Ton-That M-T, Vazquez A (2008) Physical and mechanical properties of thermoplastic starch/montmorillonite nanocomposite films. Carbohydr Polym 73 55-63 de Morals Teixeira E, Correa A, Manzoli A, de Lima Leite F, de Oliveira C, Mattoso L (2010) Cellulose nanofibers from white and naturally colored cotton fibers. Cellulose 17 595-606 de Moura MR, Aouada FA, Avena-Bustillos RJ, McHugh TH, Krochta JM, Mattoso LHC (2009) Improved barrier and mechanical properties of novel hydrox5q)ropyl methylcellulose edible films with chitosan/tripolyphosphate nanoparticles. J Food Eng 92 448—453 Dean K, Yu L, Wu DY (2007) Preparation and characterization of melt-extruded thermoplastic starch/clay nanocomposites. Compos Sci Technol 67 413 21 Duanmu J, Gamstedt EK, Rosling A (2007) Hygromechanical properties of composites of crosslinked allylglycidyl-ether modified starch reinforced by wood fibres. Compos Sci Technol 67 3090-3097... 

Chitosan/vermiculite (VMT) bionanocomposites were studied by Zhang et al. [199] who prepared their composites by solution mixing of chitosan with three different modified VMTs, viz., hydrochloride (HVMT), sodium (NVMT), and cetyl trimethyl ammonium bromide (OVMT) treated VMT. Wide-angle X-ray diffraction (WAXD), TEM, and TGA were employed in composite characterization. The authors reported that both WAXD and TEM characterization indicated that the silicate layers were dispersed into the chitosan matrix in a disordered array. It was also found that the thermal stabihty of the bionanocomposites was dependent on the clay modification process. The chitosan/HVMT nanocomposites had the best thermal performance, compared to that of neat chitosan, which was attributed to the good dispersion of acid-modified VMT and better interaction between HVMT and chitosan in the bionanocomposites. 

Chitosan has also been used as reinforcement in nanocomposites. Chitosan nanoparticles were used by Kampeerapappun et al. [204] to produce bionanocomposites with cassava starch and MMT nanocomposites. The authors reported that the addition of chitosan, due to its hydrophilicity and ability to attach to the clay surface, played a role in compatibilizing the interface between starch matrix and MMT. As a result, the starch/MMT composite film at low MMT content exhibited an improvement in tensile properties due to a reinforcement effect It was also found that the surface hydrophobicity of the composite film increased with an increase in chitosan content In association with film hydrophobicity, the water vapor transmission rate and moisture absorption were found to decrease with an increase in chitosan content. 

Choudhari, S. K. and Kariduraganavar, M. Y. 2009. Development of novel composite membranes using quatemized chitosan and Na -MMY clay for the pervaporation dehydration of isopropanol./. Colloid Interface Sci. 338 111—120. 

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