Layered-silicate polymer materials

Gilman, J. W., Kashiwagi, T., Brown, J. E., James E. T., Lomakin, S., Giannelis, E. P, and Manias, E. Flammability studies of polymer layered silicate nanocomposites, Materials and Process Affordability Keys to the Future, Book 1 (1998) (International SAMPE Symposium and Exhibition, vol 43.), 1053-1066. 

Due to recent improvements in visualization of nanoscopic material with enhanced resolution, huge advances in the characterization technology have been widespread in all the nanotechnology disciplines, compared to just about 20 years ago. A few examples of nanoscopic materials that are less than Ipm are illustrated in Figure 1.2. Current efforts in the nanoparticle—polymer field go into very small metallic and semiconductor nanoparticles with 1—2nm diameter, and use of micron-sized fillers (e.g., layered silicates) (Polymer-Nanoparticle Composites Part 1 (Nanotechnology), 2010). 

Mittal V. 2009. Polymer layered silicate nanocomposites. Materials 2 992-1057. 

Anastasiadis, S. H., Chrissopoulou, K., and Frick, B. 2008. Structure and dynamics in polymer/ layered silicate nanocomposites. Materials Science and Engineering B 152 33-39. 

The research around the use of montmorillonite to obtaining nanocomposites polymer-MMT has become even more intense. In a review, Biswas and Ray [45] described several features of polymer-MMT nanocomposite materials. Ray and Okamoto [24] reported various characteristics of polymer-layered silicate nanocomposite materials, some of these materials exhibited distinctive properties like biodegradability. Ahmadi et al. [46] reviewed synthetic routes, properties, and future applications of polymer-layered nanocomposites. Significantly, nanocomposites of PAni and PPY with MMT clay via emulsion polymerization technique [47, 48] were found to act as electrorehological fluids, sometimes denominated smart fluids. In this context, Ballav and Biswas [49, 50] reported high yield oxidative polymerization of thiophene, aniline, pyrrole, and furan by MMT— without extraneous oxidant—vis-a-vis nanocomposites formation of the corresponding polymers with MMT. 

Vaia, R. A., Ishii, H., and Giannelis, E. P. (1993). Synthesis and Properties of Two-Dimensional Nanostructures by Direct Intercalation of Polymer Melts in Layered Silicates. Chemistry Material. 5 1694-1696. 

However, the field of polymer day silicate has only started to speed up recently, mixing the appropriate modified layered silicate with synthetic layered silicates has long been known (Theng, 1979). The interest in these materials came from two important findings, first has been reported by Toyota research group of a Nylon-6 (N6)/Na-MMT nano-composites (Okada et ah, 1990) where very small amounts of layered silicate loadings resulted in the improvements of thermal and mechanical properties and second the findings of Vaia et ah (1993) about the... 

Alexandre, M. and Dubois, P. 2000. Polymer-layered silicate nano-composites preparation, properties and uses of a new class of materials. Materials Science and Engineering 28 1- 63. 

Ray, S.S. and Bousmina, M. 2005. Biodegradable polymers and their layered silicate nanocomposites In greening the 21 century materials world. Progress in Materials Science 50 962-1079. 

Vaia, R.A., Ishii, H. and Giannelis, E.P. 1993. Synthesis and properties of two dimensional nanostructures by direct intercalation of polymer melts in layered silicates. Chemistry of Material 5 1694-1696. 

Krishnamoorti, R., Vaia, R.A. and Giannelis, E. (1996) Structure and dynamics of polymer-layered silicate nanocomposites. Chemistry of Materials, 8, 1728-1734. 

Okamoto, M. (2006) Recent advances in polymer/layered silicate nanocomposites an overview from science to technology. Materials Science and Technology, 22 (7), 756-779. 

Analysis of Thermoset Materials, Precursors and Products, Martin J. Forrest, Rapra Technology Ltd. Polymer/Layered Silicate Nanocomposites, Masami Okamoto, Toyota Technological Institute. 

The dynamic mechanical thermal analyzer (DMTA) is an important tool for studying the structure-property relationships in polymer nanocomposites. DMTA essentially probes the relaxations in polymers, thereby providing a method to understand the mechanical behavior and the molecular structure of these materials under various conditions of stress and temperature. The dynamics of polymer chain relaxation or molecular mobility of polymer main chains and side chains is one of the factors that determine the viscoelastic properties of polymeric macromolecules. The temperature dependence of molecular mobility is characterized by different transitions in which a certain mode of chain motion occurs. A reduction of the tan 8 peak height, a shift of the peak position to higher temperatures, an extra hump or peak in the tan 8 curve above the glass transition temperature (Tg), and a relatively high value of the storage modulus often are reported in support of the dispersion process of the layered silicate. 

Polymers have been introduced into suitably modified galleries of a variety of clays, and related materials [63-121]. One of the most interesting results was the observation that PS chains intercalated in layered silicates do not have a Ts characteristic of the bulk material [87, 93, 94, 116]. This effect of two-dimensional surface constraints on Ts (as illustrated in Figure 7) parallels that of the three-di-... 

Batteries. Many 7t-conjugated polymers can be reversibly oxidized or reduced. This has led to interest in these materials for charge-storage batteries, since polymers are lightweight compared to metallic electrodes and liquid electrolytes. Research on polymer batteries has focused on the use of polymers as both the electrode and electrolyte. Typical polymer electrolytes are formed from complexes between metal-ion salts and polar polymers such as poly(ethyleneoxide). The conductivity is low at room temperature due to the low mobility of cations through the polymer-matrix, and the batteries work more efficiendy when heated above the glass-transition temperature of the polymer. Advances in the development of polymer electrolytes have included polymers poly(ethylene oxide) intercalated into layered silicates (96). These solid-phase electrolytes exhibit significantly improved conductance at room temperature. 

S. S. Ray, K. Yamada, M. Okamoto, and K. Ueda, New polylactide-layered silicate nanocomposites. 2. Concurrent improvements of material properties, biodegradability and melt rheology, Polymer 44, 857—866 (2003). 

Gilman, J. W., Awad, W. H., Davis, R. D., Shields, J., Harris, R. H., Davis, C., Morgan, A. B., Sutto, T. E., Callahan, J., Trulove, P. C., and DeLong, H. C. 2002. Polymer/layered silicate nanocomposites from thermally stable trialkylimidazolium-treated montmorillonite. Chemistry of Materials 14 3776-85. 

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