Nanocomposites spectroscopy

Nanocrystalline silicon Polyethylene Polymer nanocomposites Spectroscopy UV-protective film X-ray diffraction analysis... 

This is a nonpolar rubber with very little unsamration. Nanoclays as well as nanotubes have been used to prepare nanocomposites of ethylene-propylene-diene monomer (EPDM) rubber. The work mostly covers the preparation and characterization of these nanocomposites. Different processing conditions, morphology, and mechanical properties have been smdied [61-64]. Acharya et al. [61] have prepared and characterized the EPDM-based organo-nanoclay composites by X-ray diffracto-gram (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy... 

Structural characterization of the biomolecule-AMP lamellar nanocomposites using FTIR and circular dichroism (CD) spectroscopies showed no change in the... 

UV-Vis spectroscopy has been utilized to characterize the amount of copper(II) ions bound inside PAMAM dendrimers, as well as the size of resulting Cu nanocomposites upon chemical reduction [44-46]. This work has been reviewed extensively by Balogh and Tomalia [50],... 

I2W. Feng, Y. Ding, Y. Liu, and R. Lu, The Photochromic Process of Polyoxometalate-based Nanocomposite Thin Film by in situ ATM and Spectroscopy, Materials Chem. and Phys., 98, 347-52 (2006). 

Thermal treatment of the nanocomposite film formed in Scheme 6 converts the amic acid groups of the film to imides (Eq. 15). In addition to evidence by IR spectroscopy, elhpsometry showed that the film thickness decreased by ca. 15% and contact angle goniometry showed that the film became more hydrophobic (see Table 2). This thermally treated film also did not have the pH dependent permeability of redox-active ions previously described for dendrimer/Gantrez films on gold substrates [55]. 

Davis RD, Bur AJ, McBearty M et al. (2004) Dielectric spectroscopy during extrusion processing of polymer nanocomposites a high-throughput processing/characterization method to measure layered silicate content and exfoliation. Polymer 45 6487-6493... 

For appropriate comprehension of morphology and the concomitant structure-property correlations in nanocomposites, knowledge of the state and extent of nanofiller dispersion in the matrix is of paramount importance. Numerous methods have been reported in the literature in this regard, for instance, WAXD [6, 38], SAXS [8, 39], SANS [40], SEM, [6, 41], AFM [7, 42], HRTEM, STEM, EELS [43], SSNMR [44], EPRS [45], UV/vis/NIR, FTIR [46], Raman spectroscopy... 

Choudhury et al. [86] have studied the effect of polymer-solvent and clay-solvent interaction on the mechanical properties of the HNBR/sepiolite nanocomposites. They chose nine different sets of solvent composition and found that chloroform/methyl ethyl ketone (Qi/MEK) (i.e., HNBR dissolved in Ch and sepio-lite dissolved in MEK) is the best solvent combination for improvement in mechanical properties. XRD, AFM, , and UV-vis spectroscopy studies show that the dispersion of clay is best in the Ch/MEK solvent combination and hence polymer-filler interaction is also the highest. images shown in Fig. 14a, b clearly elucidate the aforementioned phenomena. Consequently, the tensile strength and modulus are found to be higher (5.89 MPa and 1.50 MPa, respectively) for the Ch/MEK system due to the minimum difference in interaction parameter of HNBR-solvent (xab) and sepiolite-solvent (Xcd)- Choudhury et al. have also studied the effect of different nanoclays [NA, , 15A, and sepiolite (SP)] and nanosilica (Aerosil 300) on the mechanical properties of HNBR [36]. The tensile... 

Ergungor describes the application of on-line Raman spectroscopy and neural networks to the simultaneous prediction of temperature and crystallinity of nylon-6 nanocomposites as a function of cooling rate. The authors prefer their neural network approach because they make use of information in the entire spectrum rather than from a few bands as most studies have done.84 Van Wijk etal. of Akzo Nobel obtained a patent on the use of a Raman spectrum of a polymeric fiber to determine dye uptake and other structural or mechanical properties based on previously developed models.85... 

Ergungor, Z. Batur, C. 8c Cakmak, M. On Line Measurement of Crystallinity of Nylon 6 Nanocomposites by Laser Raman Spectroscopy and Neural Networks /. Appl. Polym. Sci. 2004, 92, 474-483. 

Abstract. Adsorption of antioxidants (vitamins C and E) from aqueous and ethanol solutions on unmodified and partially hydrophobized nanosilica A-200 was studied using UV spectroscopy and quantum chemical methods with consideration for the solvent effects. Antioxidant power of silica nanocomposites with immobilized vitamins was evaluated by measuring the total polyphenolic index following the Folin-Ciocalteu method. It has been shown that immobilization of vitamins on silica surface leads to their stabilization. Being released from the carrier molecules of vitamins do not lose their antioxidant properties... 

Intercalated compounds offer a unique avenue for studying the static and dynamic properties of small molecules and macromolecules in a confined environment. More specifically, layered nanocomposites are ideal model systems to study small molecule and polymer dynamics in restrictive environments with conventional analytical techniques, such as thermal analysis, NMR, dielectric spectroscopy and inelastic neutron scattering. Understanding the changes in the dynamics due to this extreme confinement (layer spacing < Rg and comparable to the statistical segment length of the polymer) would provide complementary information to those obtained from traditional Surface-Force Apparatus (SFA) measurements on confined polymers (confinement distances comparable to Rp [36]. 

Polymer silicate nanocomposites offer unique possibilities as model systems to study confined polymers or polymer brushes. The main advantages of these systems are (a) the structure and dynamics of nanoconfined polymer chains can be conveniently probed by conventional analytical techniques (such as scattering, DSC, NMR, dielectric spectroscopy, melt rheology) (b) a wide range of different polymers can be inserted in the interlayer or end-grafted to the silicate... 

Keywords microstructure, microscopy, nanocomposites, properties, microscopic parameters, spectroscopy. 

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