Nylon montmorillonite

A nanocomposite material is the combination of the nanosized ultrafine powders and the polymer matrix. In such materials, organic polymer generally is a continuous phase and the nanopartides form the dispersed phase, such as Bil3-nylon 11 nanocomposites and nylon-montmorillonite nanocomposites. In this century, nanocomposite materials have become one of the most advanced composite materials. 

The second article [14] describes the in situ preparation of the nylon-montmorillonite polymer nanocomposite from the 12-aminolauric acid exchanged montmorillonite prepared in the previous article. The montmorillonite content in the polymerization varied from 1.5% to 59.6%. The general procedure was to melt -caprolactam, the organomontmorillonite prepared with 12-aminolauric acid, and 6-aminocaproic acid together with stirring at 100 °C for 30 min. The 6-aminocaproic... 

Nylon-6. Nylon-6—clay nanometer composites using montmorillonite clay intercalated with 12-aminolauric acid have been produced (37,38). When mixed with S-caprolactam and polymerized at 100°C for 30 min, a nylon clay—hybrid (NCH) was produced. Transmission electron microscopy (tern) and x-ray diffraction of the NCH confirm both the intercalation and molecular level of mixing between the two phases. The benefits of such materials over ordinary nylon-6 or nonmolecularly mixed, clay-reinforced nylon-6 include increased heat distortion temperature, elastic modulus, tensile strength, and dynamic elastic modulus throughout the —150 to 250°C temperature range. 

Y. Kojima, A. Usuki, M. Kawasumi, A. Okada, T. Kurauchi, 0. Kamigaito, Synthesis of nylon 6-clay hybrid by montmorillonite intercalated with e-caprolactam, Journal of Polymer Science Part A Polymer Chemistry, vol. 31, pp. 983-986,1993. 

In addition, two end-tethered delaminated hybrid systems prepared by in-situ polymerization - (a) Poly( -caprolactone)-montmorillonite (PCLC) and (b) nylon-6-montmorillonite (NCH) - wherein the polymer chains are end-tethered to the silicate surface via cationic surfactants [54] (Fig. 20), were also studied. 

Examples of the use of nanostructured materials for packaging applications have been given in Chaudhry et al. (2008) and references therein. One of the first market entries into the food packaging arena was polymer composites containing clay nanoparticles (montmorillonite). The natural nanolayer structure of the clay particles impart improved barrier properties to the clay-polymer composite material. Some of the polymers which have been used in these composites for production of packaging bottles and films include polyamides, polyethylene vinyl acetate, epoxy resins, nylons, and polyethylene terephthalate. 

Figure 15.11. Tensile modulus of composites made from nylon and different fillers (montmorillonite, saponite, hectorite and mica) vs. N-NMR chemical shifts of model compounds of fillers. [Adapted, by permission, from Usuki A, Koiwai A, Kojima Y, Kawasumi M, Okada A, Kurauchi T, Kamigaito O, J. Appl. Polym. Sci., SS, No.l, 1995, 119-23.]...

Chlorpropham and propham were adsorbed in large amounts by charcoal 48, 180, 182), in small amounts by exchange resins 48, 51), nylon and cellulose triacetate 340), and montmorillonite clay 48, 51, 180), and in insignificant amounts by illite and kaolinite clays 180). Hydrogen bonding was suggested as the adsorption mechanism involved 180, 340). Scott and Weber 46) found that anion exchange resins... 

A new composite material was introduced in 1987 with the discovery of a nylon-6/clay hybrid (NCH) [201]. The hybrid was prepared by the in situ thermal polymerization of s-caprolactam with 8% or less montmorillonite, the clay material containing 1-nm thick exfoliated aluminosilicate layers. It exhibited a truly nanometer-sized composite of nylon-6 and layered aluminosilicate. Figure 2.14 depicts conceptually the NCH synthesis and its fine structure. The NCH exhibited high modulus, high strength, and good gas-barrier properties. The unique and superior properties led to the commercialization of NCH. It has also created a new class of nanocomposites and worldwide interest. 

Kojima Y., Usuki A., Kawasumi M., Okada A., Kurauchi T., Kamigaito 0.,(1993). "Synthesis of nylon 6-clay hybrid by montmorillonite intercalated with 3- caprolactam". Journal of Polymer Science. Part A, Vol.31, p. 983. 

Additional specimens were prepared by melting and kneading sodium-type montmorillonite (unorganized type) and nylon 6 using a twin screw extruder at 250 °C for the purpose of comparing them with the specimens prepared as described above. This method of preparing specimens is commonly used when compounding particulate fillers with polymers. The composite material prepared in this way was called NCC (Nylon 6-Clay Composite), and the NCC was compared with the NCH. 

These specimens were labeled NCH2, NCH5 and NCH8, according to their loadings of 12-Mt. Nylon 6 1013B (molecular weight 13 000) made by Ube Industries, Ltd. was used as a specimen that contained no montmorillonite. 

Other than montmorillonite, synthetic mica, saponite and hectorite were used to synthesize a nylon 6-clay hybrid. The nano composites fabricated by using each of these types of clay were called NCH, NCHM, NCHP and NCHH. 

Silicate layers were uniformly dispersed in nylon 6 in NCH, NCHM, NCHP and NCHH at the molecular level. The thicknesses of the silicate layers were 1 nm in all of these nanocomposites, but their widths varied depending on the type of clay used. An examination of each photograph revealed that the width of the nano composites fabricated using montmorillonite and synthetic mica were about 100 nm and those of the nanocomposites fabricated using saponite and hectorite were about 50 nm. 

It was inferred from all of these results that montmorillonite in all types of clay can bond most strongly with nylon 6 and that the bond strength weakens in the order of synthetic mica > saponite hectorite. Figure 12 shows the N-NMR chemical shift as an indicator of bond strength and the flexural... 

A nylon 66 clay nanocomposite was produced using the dry-compound method [26]. Co-intercalation organophihc clay was used as the clay base. Na-montmorillonite was first processed using hexadecyl trimethyl ammonium ions and epoxy resin. It was then kneaded using a twin screw extruder to make a clay nano composite. As the amount of clay that was added increased, the amount of y (gamma) phases increased. This is thought to be due to the strong interactions between the nylon 66 chains and the sinface of the clay layers. 

Figure 28 shows the relationships between the amount of inorganics in the clay and the gas permeability coefficient. The gas permeabiUty coefficient decreased as the amount of added clay increased. The gas barrier performance of PPCN-5 increased by 1.7 times. It has been reported that the barrier performance of the nylon-clay nanocomposites and polymer-clay nanocomposites was improved. This barrier effect is explained as being attributed to the geometrical detour effect of the dispersed nanosized silicates. The barrier effect of PPCN, however, was smaller than that of the nylon-clay nanocomposites. hi the case of the nylon-clay hybrid, the addition of 1.8 wt % of mont-morillonite caused its hydrogen permeability to decrease to 70%. In the case of PPCN, about 3 wt % of montmorillonite must be added to obtain the same... 

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