Fillers characterization

It was observed that the surface acidify of the fillers influences the bending and stretching vibrational frequencies of the water physically adsorbed on the filler surface [6, 14]. The conductivity of composite membranes and maximum power density of DMFCs at 145 °C appear to be related to the characteristics of the water adsorbed oti the filler particles [6,14]. Inorganic fillers characterized by acidic properties undergo a strong interaction with water and enhance the DMFC performance at high temperatures. The self-diffusimi coefficients of water and methanol have been determined over... 

T. Schauer has used modified flow field flow fractionation to determine the particle size of each individual constituents of a three component mixture of paint hinder, pigment and filler, characterized by relatively broad and overlapping distributions. He was able to follow the changes on mixing them [61]. 

Representative set of weldments was examined site welds (with pearlitic type weld metal) and two types of site weld repair zones with different welding technologies using Cr-Ni filler metals and Ni-based alloy. Results of AUGUR 4.2 inspection were compared with manual ultrasonic inspection ones in terms of defect detection, characterization, positioning and sizing in order to estimate correlation between these data. 

Carbon blacks are typical fillers for reinforcing rubber. An extensive literature has been devoted to the manufacture, structure, and characterization of carbon blacks, as well to their effects as fillers in polymers. Some specific and more detailed information can be found in Refs. [38,48]. 

It is precisely the loosening of a portion of polymer to which the authors of [47] attribute the observed decrease of viscosity when small quantities of filler are added. In their opinion, the filler particles added to the polymer melt tend to form a double shell (the inner one characterized by high density and a looser outer one) around themselves. The viscosity diminishes until so much filler is added that the entire polymer gets involved in the boundary layer. On further increase of filler content, the boundary layers on the new particles will be formed on account of the already loosened regions of the polymeric matrix. Finally, the layers on all particles become dense and the viscosity rises sharply after that the particle with adsorbed polymer will exhibit the usual hydrodynamic drag. 

The strength of the filler skeleton may be characterized by the complex dynamic modulus measured at low frequencies [24]. The authors note that when c > ccr the yield point should be viewed as a sum of two components ... 

Earlier in [274] it was proposed that the increase of polymer surface by the introduced filler plays the decisive role in the formation of regions characterized... 

These parameters refer separately to the filler and the matrix. However, besides these parameters, there is another factor, which is of cardinal importance for the characterization of a composite system, which is the effectiveness of the bond between matrix and filler in transferring stresses across the interface. 

FIGURE 22.5 Schematic view of kinetically aggregated filler clusters in mbber below and above the gel point <1>. The left side characterizes the local stmcture of carbon black clusters, built by primary particles and primary aggregates. (Every black disk in the center figure [ and on the right-hand side

primary aggregate.) (From Kliippel, M. and Heinrich, G., Kautschuk, Gummi, Kunststojfe, 58, 217, 2005. With permission.)... 

Future work in this area will involve the extension of these techniques to other temperatures in an effort to better characterize the overall reaction kinetics of these two processes. In addition, degree of cure obtained through isothermal DSC measurements will be compared with the fraction of acetylene consumed as measured by isothermal FTIR experiments for the same temperature and time. Also, the effect of the incorporation of metal fillers on the isomerization and crosslinking reactions will be addressed. 

Most elastomers require reinforcing fillers to function effectively, and NMR has been used to characterize the structures of such composites as well. Examples are the adsorption of chains onto filler surfaces [275], the immobilization of these chains into "bound rubber" [276], and the imaging of the filler itself [277]. 

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