Polymer nanocomposites content

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... 

Fig. 12 Temperature coefficient of the resistivity of synthesized metal(metal oxide)-polymer nanocomposites vs. metal content...

Thin-film metal (metal oxide)/polymer nanocomposites with different inorganic phase contents were obtained by using the cold-wall vacuum co-deposition technique. A range of metals was shown to be applicable to form nanocomposite thin films with PPX, i.e., Al, Ti, Pd, and Sn. AFM studies show the metal nanoparticles to have a size of 7-50 nm. Within the composite the polymer forms more or less spherical globules with a maximum size of about 200 nm. The interfacial regions between neighbouring polymeric spherulites contain nanoparticles of the inorganic filler. 

The rheological behavior of these materials is still far from being fully understood but relationships between their rheology and the degree of exfoliation of the nanoparticles have been reported [73]. An increase in the steady shear flow viscosity with the clay content has been reported for most systems [62, 74], while in some cases, viscosity decreases with low clay loading [46, 75]. Another important characteristic of exfoliated nanocomposites is the loss of the complex viscosity Newtonian plateau in oscillatory shear flow [76-80]. Transient experiments have also been used to study the rheological response of polymer nanocomposites. The degree of exfoliation is associated with the amplitude of stress overshoots in start-up experiment [81]. Two main modes of relaxation have been observed in the stress relaxation (step shear) test, namely, a fast mode associated with the polymer matrix and a slow mode associated with the polymer-clay network [60]. The presence of a clay-polymer network has also been evidenced by Cole-Cole plots [82]. 

Graphene-polymer nanocomposites share with other nanocomposites the characteristic of remarkable improvements in properties and percolation thresholds at very low filler contents. Although the majority of research has focused on polymer nanocomposites based on layered materials of natural origin, such as an MMT type of layered silicate compounds or synthetic clay (layered double hydroxide), the electrical and thermal conductivity of clay minerals are quite poor [177]. To overcome these shortcomings, carbon-based nanofillers, such as CB, carbon nanotubes, carbon nanofibers, and graphite have been introduced to the preparation of polymer nanocomposites. Among these, carbon nanotubes have proven to be very effective as conductive fillers. An important drawback of them as nanofillers is their high production costs, which... 

Similar to noble metal nanoparticles, Co nanoparticles can be prepared by incorporation of C0CI2 (which is almost insoluble in toluene) in the PS-( -P2VP micelles followed by reduction. This results in very small spherical particles (below Inm in diameter), the thermal treatment of which at 200°C for 2hr yields spherical nanoparticles with diameters in the range of 3-5 nm [38]. In the solid state these metal-polymer nanocomposites display extraordinarily high magnetization value at comparatively low Co content that is, we obtained a tenfold increase of the specific magnification density. 

Lii, C. L., Cheng, Y. R., Liu, Y. R, Liu, R, and Yang, B. 2006. A facile route to ZnS-polymer nanocomposite optical materials with high nanophase content via y-ray irradiation initiated bulk polymerization. Adv. Mater. 18 1188-1192. 

Up to now we considered pol5meric fiiactals behavior in Euclidean spaces only (for the most often realized in practice case fractals structure formation can occur in fractal spaces as well (fractal lattices in case of computer simulation), that influences essentially on polymeric fractals dimension value. This problem represents not only purely theoretical interest, but gives important practical applications. So, in case of polymer composites it has been shown [45] that particles (aggregates of particles) of filler form bulk network, having fractal dimension, changing within the wide enough limits. In its turn, this network defines composite polymer matrix structure, characterized by its fractal dimension polymer material properties. And on the contrary, the absence in particulate-filled polymer nanocomposites of such network results in polymer matrix structure invariability at nanofiller contents variation and its fractal dimension remains constant and equal to this parameter for matrix polymer [46]. 

Pillai et al. described a comparison between two chemical functionalization strategies for the amine functionalization of multiwalled CNTs. The modified CNTs with optimum amine content were used to prepare PLA/CNT nanocomposites through solution casting method. The polymer nanocomposite thus prepared showed improved thermal properties when compared to the neat PLA [65]. 

In this method, semiconductor nanoparticles are dispersed directly in monomeric solution prior to a polymerization process. Guan et al. [242] used this method for synthesis of transparent polymer nanocomposites with high ZnS nanophase contents using a one-pot route via in-situ bulk polymerization. Uniform distribution of ZnS nanoparticles in the polymer matrix was observed due to covalent bonding between ZnS nanoparticles and the polymer matrix. This uniform distribution improved the thermal stability and mechanical properties of the nanocomposite. The nanocomposites also exhibited good transparency and adjustable refractive index due to controlled structore and ZnS content. 

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