Polymer Nanocomposites montmorillonite

R. A. Vaia, B. B. Sauer, O. K. Tse, and E. P. Giannelis, Relaxations of confined chains in polymer nanocomposites Glass transition properties of poly(ethylene oxide) intercalated in montmorillonite, J. Polym. Sci. B Polym. Phys. 35(1), 59-67 (1997). 

Vaia, R. A., Liu, W., and Koemer, H. Analysis of small-angle scattering of suspensions of organically modified montmorillonite Implications to phase behavior of polymer nanocomposites, J. Polym. Sci. B.Polym. Phys. (2003), 41, 3214-3236. 

In the previous several years, various nanoparticles have been assembled into pairs to fabricate polymer nanocomposites, such as clay/silica (45), clay/carbon black (43), CNTs/clay (41,42), and CNTs/Titanium (38). Polymer/CNTs/clay ternary composite is one of most important multiphase systems with interesting synergistic effect, where sodium based montmorillonite (MMT) are the most commonly used layered clay. In this chapter, we will select some typical examples to demonstrate the importance and synergies of using CNTs and clay together in the preparation of polymer nanocomposites. 

Properties of Polymer Nanocomposites Based ON Organomodified Na -Montmorillonite... 

Special methods of incorporation alkyl peroxide bridging to vinyl containing siloxane polymers used for conductive applications improved curing characteristics decreased by the presence of carbon black crosslinking based on platinum catalyzed polyvinylmethyl siloxane and polymethyl hydrogen siloxane is not inhibited by carbon black in situ silica formation in fonnation of PDMS nanocomposite, montmorillonite was delaminated in polymer prior to crosslinking ... 

The prospects of application of the montmorillonite-polymer nanocomposites as high performance materials in several applications have been discussed. 

In terms of nanocomposite reinforcement of thermoplastic starch polymers there has been many exciting new developments. Dufresne [62] and Angles [63] highlight work on the use of microcrystalline whiskers of starch and cellulose as reinforcement in thermoplastic starch polymer and synthetic polymer nanocomposites. They find excellent enhancement of properties, probably due to transcrystallisation processes at the matrix/fibre interface. McGlashan [64] examine the use of nanoscale montmorillonite into thermoplastic starch/polyester blends and find excellent improvements in film blowability and tensile properties. Perhaps surprisingly McGlashan [64] also found an improvement in the clarity of the thermoplastic starch based blown films with nanocomposite addition which was attributed to disruption of large crystals. 

The most commonly studied polymer nanocomposites are clay-based nanocomposites, mainly with montmorillonite (MMt) as layered silicate filler (Scheme 15.12). Upon incorporation of organomodihed clays (organoclays) into a polymer matrix, two nanomorphologies (Scheme 15.13) can be obtained, either intercalation of the polymer chain in between the clay platelets keeping the stacking of the sheets, or exfoliation of the clay platelets with a disordered dispersion of the inorganic sheets in the polymer. 

Botana et al. [50] have prepared polymer nanocomposites, based on a bacterial biodegradable thermoplastic polyester, PHB and two commercial montmorillonites [MMT], unmodified and modified by melt-blending technique at 165°C. PHB/Na and PHB/ C30B were characterized by differential scanning calorimetry [DSC], polarized optical microscopy [POM], X-ray diffraction [XRD], transmission electron microscopy [TEM], mechanical properties, and burning behavior. Intercalation/exfoliation observed by TEM and XRD was more pronounced for PHB30B than PHB/Na,... 

Koo and co-workers [78] attempted to develop polyamides 11 and 12 with enhanced flame retardancy and thermal and mechanical properties by the incorporation of montmorillonite clays, silica and carbon fibre-polymer nanocomposites. Flammability properties of the nanocomposites were compared with those of the virgin polyamides, using cone calorimetry with an external heat flux of 50 kW/m. Cone calorimetry was also used in an evaluation of polyamide 6 - anion modified Mg/Al interlayer formulation [79]. The data from the cone calorimeter shows that the heat production rate (HPR) and mass loss weight of the sample with 5 wt% MgAl(H-DS) decrease considerably to 664 kW/mVs and 0.161 g/mVs from 1064 kW/mVs and 0.252 g/mVs... 

Wang, Z. and Pinnavaia, T. J. 1994. Clay-polymer nanocomposites formed from acidic derivatives of montmorillonite and an epoxy resin. Chemistry of Materials 6 468-474. 

Sibold, N., Dufour, C., Gourbilleau, R, Metzner, M. N., Lagreve, C., Le Puart, L., Madec, P. J., and Pham, T. N. 2007. Montmorillonite for clay-polymer nanocomposites Intercalation of tailored compounds based on succinic anhydride, acid and acid salt derivatives A review. Applied Clay Science 38 130-138. 

Depending on the distribution of micro/nanofiller in the polymer matrix, the composites may be classified as microcomposites or nanocomposites. These two types of composites differ significantly with respect to their properties. The nanocomposites show improved properties compared to pure polymer or that of microcomposites. It started only back in 1990, when Toyota research group showed that the use of montmorillonite can improve the mechanical, thermal, and flame retardant properties of polymeric materials without hampering the optical translucency behaviour of the matrix. Since then, the majority of research has been focused in improving the physicochemical properties, e.g. mechanical, thermal, electrical, barrier etc. properties of polymer nanocomposites using cost effective and environmental friendly nanofillers with the aim of extending the applications of these materials in automotive, aerospace, construction, electronic, etc. as well as their day to day life use. The improvements in the majority of their properties have invariably been attributed... 

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