Nanocomposite characterization

Development of new types of nanofillers used as reinforcement in nanocomposites entails necessity of introducing and improving methods of nanocomposites characterization. Insight into mechanisms of forming nanocomposite and its molecular 

Structure helps to better control of processes and enables design of nanocomposites properties according to the need. Following are the main aspects that should be defined in order to characterize structure of nanocomposites [59]  

Numerous nanocomposite characterization methods are available thermogravimetric analysis (TGA), differential scanning calorimetry [DSC], transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), IR spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, dielectric relaxation spectroscopy, atomic force microscopy [AFM], electron spin resonance, continuous-wave and pulsed ESR spectroscopy and others [59]. Among all of the methods, TGA, DSC, wide-angle scattering diffraction [WAXS], and TEM are the most commonty used and will be discussed in detail. 

TGA is most commonly used for evaluation thermal stability of nanocomposites filled with montmorillonite, clay, or carbon nanotubes. High-resolution TGA is applicable while determining the presence of any excess of surface modification molecules unbound to the surface. It is very important to know this parameter, especially if the nanofiller is to be added to pol5mier at high temperatures. In such a situation, modification molecules may have lower thermal degradation, which will negatively affect the properties of the nanocomposite. The commercially treated filler, in comparison with the second one, clearly exhibits an extra degradation peak at lower temperature, which indicates the presence of modification molecules not bonded with filler surface 

In general, the DSC analysis ofnanocomposites generates information on glass transition temperature (T ), ciystallization temperature (re), melting temperature (TiJ, enthalpy of crystallization (//c), degree of crystallinity (Ae), and enthalpy of melting (W ) (Fig. 21.35) [59, 61, 62]. 

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Keywords Graphene, conjugated polymers, nanocomposites, characterization, properties, optoelectronic application, biological application... 

Adhikari, R. and Michler, G. H. 2009. Polymer nanocomposites characterization by microscopy. 

Clay organization in rubber nanocomposites Characterization techniques... 

Nagendiran, S., Alagar, M., Hamerton, I. Octasilsesquioxane-reinforced DGEBA and TGDDM epoxy nanocomposites Characterization of thermal, dielectric and morphological properties. Acta Mater. 58, 3345-3356 (2010)... 

L. Cauvin, D. Kondo, M. Brieu, N. Bhatnagar, Mechanical properties of polypropylene layered silicate nanocomposites characterization and micro-macro modelling. Polymer Testing 29 (2) (2010) 245-250. 

Inorganic-polymer nanocomposites characterized by exceptional dielectric constant are often called artificial dielectrics . Artificial dielectrics are created when isolated particles become polarized due to the presence of an applied electric field. These novel nanocomposite artificial dielectrics have the potential to posses high dielectric constants (>100) at high frequencies and the low processing temperature associated with polymers. Such a combination of properties is not found in other capacitor materials [180]. Polymer matrices like PMMA, poly(vinylidene fluoride) (PVDF), PS, and polyurethane (PU) have been used. Owing to their physicochemical properties, they represent suitable polymer components for embedding nanoscopic functional inorganic fillers (Table 2). 

Keywords Coordination catalyst In situ polymerization Montmorillonite Nanocomposite characterization Polyolefin/clay nanocomposites Preparation... 

Fourier transform infrared spectroscopy (FTIR) may find a difference between the bonding in different types of nanocomposites however, the variations could be minute and hence this is an unreliable method for nanocomposite characterization [53, 54]. Nascimento et al. [55] presented for the first time the resonance Raman characterization of a polymer/clay nanocomposite formed by aniline polymerization in the presence of MMT. 

THE CONDITIONS OF REDOX SYNTHESIS OF METAL/ CARBON NANOCOMPOSITES AND THE NANOCOMPOSITES CHARACTERIZATION... 

First and paramount method of nanocomposites characterization is, undoubtedly, transmission dectron microscopy (TEM), which allows one to observe the particle shape, to determine particle sizes, to control the homogeneity of the composite and to obtain the histogram of nanoparticle sizes (Figs. 1, 2). TEM (especially axial bright fidd microscopy) is the most informative method of characterization with the resolution up to units of angstroms allowing visualization of the lattice plane and measurement of interplanar distances of nano-partides. However, its application to polymer composites is hindered due to charge instability of some polymers (such as PVA [39], or PVDF [35]) and by the difficulty of sample preparation. 

Another informative method of nanocomposites characterization is the wide angle X-ray structural analysis (WAXS) and especially small-angle X-ray analysis (SAXS). X-ray analysis allows one to determine the lattice parameters of nanoparticles and, as it was found [2, 12] for the majority of suliides and oxides, the small particles exhibit the same lattice parameters and crystallographic structure as bulk substances up to the size of 20 A. At this size, the deformation of the lattice takes place which accompanies the transition to cluster structure with minimized full energy, induding free energy of the surface [11]. 

Narayanan R A, Thiyagarajaii P, Zhu A J, Ash B J, Shofner M L, Schadler L S, Kumai" S K and Sternstein S S (2007) Nanostructural features in silicarpolyviiiyl acetate nanocomposites characterized by small-angle scattering. Polymer 48 5734-5741. Levresse P, Feke D L and Manas-Zloczower I (1998) Analysis of the formation of bound poly(dimethylsiloxane) on silica, Polymer 39 3919-3924. 

Haq, M., Brngueno, R., Mohanty, A.K., Misra, M., 2009a. Bio-based unsaturated polyester/ layered sihcate nanocomposites characterization and thermo-physical properties. Composites Part A Apphed Science and Manufacturing 40, 540—547. 

Polymer Nanocomposites Characterized by Thermal Analysis Techniques... 

Zhong H, Yuan R, Chai Y et al (2011) In situ chemo-synthesized multi-wall carbon nanotube-conductive polyaniline nanocomposites characterization and application for a glucose amperometric biosensor. Talanta 85 104—111... 

Suresh R, Giribabu K, Manigandan R et al (2014) Fe203 polyaniline nanocomposite characterization and unusual sensing property. Mater Lett 128 369-372... 

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