MMT nanoclays

PP/Montmorillonite (MMT) nanoclay based composite was prepared by melt compounding with MA-g-PP in a twin-screw extmder and an internal mixer. Test specimens were prepared by compression molding. Mechanical properties such as tensile modulus, tensile strengfli and maximum percentage strain were measured. The clay dispersion was investigated using WAXD and SEM. 

In the film study, MMT nanoclay exfoliated in a masterbatch was let down to 3% clay loading in 20 and 50 melt-index LLDPE resins. A second batch of these materials was each... 

This chapter explores the use of furfuryl alcohol (FA) both as the initial medium for dispersing nanopartides of cellulose whiskers (CW) or montmorUlonite (MMT) nanoclays and as the monomer precursor for in-situ polymerization of the PNC matrix. In general, nanopartides prepared from biomass or from minerals possess an abundance of built-in surface functionality, and this can be exploited in the reactive molding approach to achieve their dispersion in PNCs. 

Compositematerialcontainingatleastonephasewithconstituentsofl-lOOmn in size can be termed nanocomposites. Nanoparticles commonly used in the nanocomposite include single-walled carbon nanotube (SWCNT), double-walled carbon nanotube (DWCNT), multi-walled carbon nanotubes (MWCNT), carbon nanofiber (CNF), graphite nanoplatelet (GNP), mont-morillonite (MMT), nanoclay and polyhedral oligomeric silsesquioxanes (POSS). Other nanoparticles, such as SiOj, AljOj, TiOj and nanosilica are also used in the nanocomposite. The potential benefits of the nanoparticles for structural and multifunctional nanocomposites are sunamarized below. 

TEM photomicrographs of a PP-3% MMT/PC-2% CNT = 60/40 wt% blend. The TEM illustrates that the carbon nanotubes (CNT) are exclusively located and nicely dispersed in the polycarbonate phase (A) and most of the MMT nanoclay is located at the interface between PP and PC in this cocontinuous blend (B). Thus, a nanoclay migration from the prefilled PP phase could be observed during melt-mixing of the blends. (From P. Potschke, B. Kretzschmar, and A. Janke, Compos. Sci. Technol. 67,855-860,2007. With permission.)... 

Fig. 3.14 (a, b) Montmorillonite (MMT) nanoclay. (Wallace 2015). Source [https //nice.asu.edu/ nano/montmorillonite-mmt-nanoclays-ashpalt]... 

Wallace T, Center for Nanotechnology in Society, Arizona State University, Montmorillonite (MMT) Nanoclays in Ashpalt, [Online] Available from https //nice.asu.edu/nano/montmOTil lonite-mmt-nanoclays-ashpalt [Accessed 9th Sep 2015]... 

MMT nanoclays are also known as 2 1 phyllosilicates and possess a layer of octahedral alumina and two linked tetrahedral silicate layers, illustrated in Rgure 6.2. A hexagonal symmetry is formed from one silicate atom and four joint oxygen atoms on the outer tetrahedral layer. Meanwhile, each aluminum atom is bonded with six oxygen atoms in the shape of an octahedron (i.e., a polyhedron with eight faces) on the... 

HNTs are different from MMT nanoclays with respect to their fundamental structure. Consisting of an octahedral aluminum layer and a tetrahedral silicate layer with a hydrated characteristic, HNTs are also known as 1 1 phyllosUicate.. Similar to a coil, the structure of HNTs is in the form of multilayered tubes rolled up by layers of aluminosilicates as observed in Figure 6.3. HNTs belong to the kaolin famUy with a chemical formula of Al2Si205(0H)4 H20 (Liu et al., 2007). HNTs are naturally abundant and available as hydrated clays with n = 2 for the water content. In general, the evaporation process of natural kaolin leads to the HNT structure (Lvov and Abdullayev, 2013). Lvov and Abdullayev (2013) also found the HNT length is approximately 0.5—2 pm whereas the inner and outer diameters are about 10—30 nm and 50—70 nm, respectively. Moreover, ecofriendly HNTs have become more cost competitive when compared with CNTs. Their unique cylindrical tubular... 

Usuki et al. (1993) introduced MMT nanoclay modification by studying the cation-exchange reaction of MMT nanoclays with an amino acid solution. It was found that the interlayers of MMTs were modified by an amino acid to produce new clay-intercalated stmctures. The typical case can be represented by the addition of modified MMTs on nylon 6 matrices for better clay dispersion with the reduction of molecular weight (MW) of nylon 6/clay nanocomposites (Usuki et al., 1993). A new network was further established between nylon 6 and MMT interlayer surfaces with the aid of ammonium cations. 

Capkova et al. (2006) tried to intercalate Na" " MMT nanoclays with stearic acid and amine. After Na" " MMT nanoclays were mixed with stearic acid and/or octadecylamine, it was shown that stearic acid could not replace Na on MMT layers whereas octadecylamine was intercalated into MMTs at the mixing reaction temperature of 80 °C. 

Figure 13.17 Composite TVA thermograms for the non-oxidative degradation of a condensation-cured, bimodal silicone elastomer fUled with 0-8 wt% O-MMT nanoclay platelets. A-E correspond to 0,1, 2, 4 and 8 wt% O-MMT loading, respectively.

Figure 13.18 SATVA differential distillation traces for the products of the thermal degradation of a series of condensation-cured silicone elastomers filled with 0-8 wt% O-MMT nanoclay. A-E correspond to 0,1,2,4 and 8 wt% clay loadings. The left shows the full scale product profile having only 2 peaks (i and ii) making up 95% hy volume of the total distillate. On the right is an expansion of the region from -190 to -40 C and shows the further eight minor products (i-vii) which make up the remainder of the distillate.

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