Analog nanocomposite

Analogous nanocomposites were also prepared based on polyimide analogs, such as polyoxazolines, containing trietiioxysilane groups. ... 

However, during long exposures to medium-temperature operating conditions, e.g. 1000°C, spinel formation is certainly expected. Wang etal.60 demonstrated this for the Ni-alumina system, showing the diffusion of Ni atoms to the free surface of the nanocomposite, followed by the formation of a nickel spinel surface coating which then limits the kinetics of subsequent oxidation. In this case the formation of a spinel surface layer may be beneficial to mechanical properties, since the reaction results in a volume increase, and the formation of compressive residual stresses. An analogous behavior was reported for ceramic particle nanocomposites, where oxidation of SiC particles results in an increase in volume and compressive residual stresses.61... 

By analogy with the works which dealt with cellulose micro crystal-reinforced nanocomposite materials, microcrystals of starch [95] or chitin [96, 97] were used as a reinforcing phase in a polymer matrix. Poly(styrene-co-butyl acrylate) [95,96], poly(e-caprolactone) [96], and natural rubber [97] were reinforced, and again the formation of aggregates or clustering of the fillers within the matrices was considered to account for the improvement in the mechanical properties and thermal stability of the respective composites processed from suspensions in water or suitable organic solvents. 

The multilayer nanocomposite films containing layers of quasi-spherical Fe nanoparticles (d — 5.8 nm) separated by dielectric layers from boron nitride (BN) are synthesized by the repeated alternating deposition of BN and Fe onto a silicon substrate [54]. In this work the authors managed to realize the correlation in the arrangement of Fe nanoparticles between the layers the thin BN layer deposited on the Fe layer has a wave-like relief, on which the disposition of Fe nanoparticles is imprinted as a result, the next Fe layer deposited onto BN reproduces the structure of the previous Fe layer. Thus, a three-dimensional ordered system of the nanoparticles has been formed on the basis of the initial ordered Fe nanoparticle layer deposited on silicon substrate [54]. The analogous three-dimensional structure composed of the Co nanoparticles layers, which alternate the layers of amorphous A1203, has been obtained by the PVD method [55]. 

The maximal Y value for Cu-PPX catalyst is 1150 [116], It is much more than the activity of all known catalysts of this reaction. For comparison, the same reaction of C-Cl bond metathesis was investigated on the special prepared catalyst containing 1 mass% of high-dispersed metallic Cu deposited on silica. In conditions analogous to those of the reaction with the nanocomposite Cu-PPX film, Y for this catalyst was 4. Moreover, it has low selectivity in this case the formation of by-products from condensation processes takes place along with the main reaction, whereas Cu-PPX catalyst gives monochlorosubstituted decanes only [116]. 

In close analogy to the PCL based nanocomposites, the terminal zone dependence of G and G" for the 2 and 5 weight % samples, show non-terminal behavior with power-law dependencies for G and G" much smaller than the expected 2 and 1 respectively. Furthermore, like the PCL based nanocomposites, there also appears to be a gradual decrease in the power-law dependence of G and G" with increasing silicate loading. 

On a global scale, the linear viscoelastic behavior of the polymer chains in the nanocomposites, as detected by conventional rheometry, is dramatically altered when the chains are tethered to the surface of the silicate or are in close proximity to the silicate layers as in intercalated nanocomposites. Some of these systems show close analogies to other intrinsically anisotropic materials such as block copolymers and smectic liquid crystalline polymers and provide model systems to understand the dynamics of polymer brushes. Finally, the polymer melt-brushes exhibit intriguing non-linear viscoelastic behavior, which shows strainhardening with a characteric critical strain amplitude that is only a function of the interlayer distance. These results provide complementary information to that obtained for solution brushes using the SFA, and are attributed to chain stretching associated with the space-filling requirements of a melt brush. 

Intercalation of electroactive polymers such as polyaniline and polypyrrole in mica-type layered silicates leads to metal-insulator nanocomposites. The conductivity of these nanocomposites in the form of films is highly anisotropic, with the in-plane conductivity 10 to 10 times higher than the conductivity in the direction perpendicular to the film. Conductive polymer/oxide bronze nanocomposites have been prepared by intercalating polythiophene in V2O5 layered phase, which is analogous to clays. °° Studies of these composites are expected not only to provide a fundamental understanding of the conduction mechanism in the polymers, but also to lead to diverse electrical and optical properties. 

So, the mean size of metal or semiconductor crystals in cryochemically prepared PPX nanocomposites depends almost not at all on the nature of such crystals but is determined by the polymer matrix. In particular, data on the width of the nanocrystals plasmon band [44] (cf. Figures 2.5 and 2.6) specify that d of nanocrystals formed from Ag clusters in CNPPX is, approximately, in one and a halftime less than that of analogous nanocrystals in PPX and CIPPX. 

A similar change of preferred orientation [111] to [200] was observed by the authors of the paper [35] with an increase in Ni concentration in the Ti-Ni-N nanocomposite. This phenomenon was also observed in the range of up to 10 at.% Ni. The average grain size decreased from 16 to 7 nm (400°C). At the same time, the hardness maximum of nanocomposites that contain soft metal phase Cu and Ni [35,44,52] corresponds to somewhat lower values of their concentrations in comparison with silicon, that is, 5-10 at%. The analogous data were also obtained for V2N-Si3N4 [39],... 

Analogous results have been recently obtained by other research groups. The effect of -COOH- and phenol-functionalized CNTs on mechanical, dynamic mechanical and thermal properties of polypropylene (PP) nanocomposites were considered, and the results confirmed in both cases that the percentage crystallinity was found to increase on phenol and carboxylic functionalization of MWNTs. 

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