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Microstructural variation

This microstructure variation has not been observed with homopolymers synthesized with Na+. For Rn > 3000, % (1,2) - 12%. [Pg.318]

Furthermore, microstructural variations of cis, trans, and vinyl contents have no discernible effect on the relation between g and g" of Figures 3-5. Since the same linear butyllithium polymers containing 10% vinyl isomer were used as reference in calculating g and g", it is likely that microstructural differences have been cancelled. [Pg.101]

This method however assumes that a static calibration is sufficient for a dynamic sample. It corresponds that a PEM sample in a fuel cell has well defined and fixed relaxation times. If the PEM however is truly dynamic and undergoes microstructural variation or other evolution then the relaxation times will change and the image will change even though the water content is not changing. For more reliable approach, it is feasible to use mapping of relaxation parameters in the PEM, because relaxation parameters such as T1 and T2 also depends on water contents as performed by Balcom et al.15... [Pg.209]

Microstructure variation in both polybutadiene and polyisoprene polymers has been realized by using alkyllithium initiators in the presence of polar modifiers. [Pg.58]

Processing conditions required to attain desirable composite properties can be defined more easily if the factors controlling composite microstructure are understood. Such factors include type of precursors employed and the composite s processing history. The microstructure of the matrix may contribute to the performance of the fibers and influence the properties of the composite. Reviewed are experiments to determine matrix micro-structural features, how microstructural variations are achieved, and ways in which thermal expansion and fracture behavior relate to microstructure. [Pg.388]

The exact role of matrix microstructure in determining the physical properties of C-C composites is difficult to determine precisely because the microstructural variations and fiber-matrix interactions are highly complex. Some insight into the importance of... [Pg.391]

Flardness tests are widely used as a non-destructive method of estimating the yield stress of metal products, to check whether heat or surface treatments have been carried out correctly. The test is less common for plastics, partly because such treatments are not used, and partly because viscoelasticity makes the indentation size decrease with time. Recently, nano-indentation has been used to examine microstructural variation in polymers. This section considers the case where the indentation depth is much smaller than the product thickness, whereas Section 8.2.6 considers the case of the indenter penetrating the product. [Pg.241]

Hu, J., Li, H., and Huang, X. (2007). Electrochemical behavior and microstructure variation of hard carbon nano-spherules as anode material for Li-ion batteries. Soiid State Ionics, 178(3-4) pp. 265-271. [Pg.247]

These observations are corroborated by the XRD patterns of the samples obtained under conditions leading to the microstructures in Figure 2.19a and 2.19b. These are shown in Figure 2.20a and 2.20b, respectively. Detailed analysis of the X-ray peaks reveals that such treatment yields a mixture of WO2/WO3, rather than either of the two oxides being the predominant phase. Thus, the role of controlled oxygen potential in the ambient and its effect on microstructural variation of a given phase are clearly brought out. [Pg.37]

Mechanical Properties The variation of mechanical properties dted in the Uterature can be strongly attributed to microstructural variations in the carbon content, grain size, inhomogeneities, and residual porosity. The values given here are taken from reviews given by Lipp [132], Thevenot [137, 528, 529], and Greim and Schwetz [530]. [Pg.198]

When two or more components are present in a thin film, there is the potential for phase separation and therefore a wide range of microstructural variation. In addition, for solution-processed materials, the solvent acts as a further component that is controllably removed during fabrication. Therefore, in the case of small-mole-cule/polymer systems, there can be several factors that determine the overall phase behavior first, the thermodynamics of mixing between components and the balance of entropic and enthalpic contributions to the free energy of mixing, AG ixi second, the interaction between solution and substrate or atmosphere interfaces and finally, the kinetics of solvent evaporation and changes to the solution that this induces, such as viscosity variation or phase separation within the solution. It should be noted that these processes are often far from thermodynamic equilibrium leading to a film microstructure that can sometimes be difficult to predict. [Pg.222]

Evaluation of dynamic fracture characteristics of 9Cr-lMo ferritic steel was carried out for normalised tempered (N T), aged (at 1013 K for 1-2 h) and welded conditions (with PWHT). The drop-weight nil-ductility transition temperatures (Tj ) were 248 K, 248 K and 268 K respectively for N T, aged and welded conditions. Despite the difficulties in crack-profile measurement and the uncertainties in fracture loads due to microstructural variation in HAZ of the drop-weight specimens, the particular procedure developed enabled determination of conservative estimates of at/below T. j. from instrumented drop-weight tests which are... [Pg.127]

Table3.1-26 Effect of microstructure variation on fracture toughness Kic at room temperatnre for a Ti-25Al-10Nb-3V-1MO aUoy... Table3.1-26 Effect of microstructure variation on fracture toughness Kic at room temperatnre for a Ti-25Al-10Nb-3V-1MO aUoy...
MICROSTRUCTURE VARIATION IN POLYBUTADIENE MICROSTRUCTURE (VINYL. CIS AND TRANS)... [Pg.22]

Table 1. Polymer Microstructure Variation with Conditions... Table 1. Polymer Microstructure Variation with Conditions...
It is the value of n in equation (4.2) that is used to express a measure of the ISE of a material. Equation (1.6) gives the relationship of Vickers hardness to load, and for there to be no dependence of hardness on indentation size, n in equation (4.2) must equal 2. When hardness changes as the half diagonal a decreases, then clearly the relationship between P and a is not simple and n will not equal 2. Deviations from n = 2.0 are then a measure of the ISE effect and for a given ceramic, variations in n will be a measure of microstructural variations, surface layers, surface chemistry, or mechanochemical effects. [Pg.67]

Our SRM results are also consistent with 30 years of test data from a variety of sources (Table 1). Indeed, our experience with the six billets studied for the SRM as well as billet E, and data from the old stress rupture and fracture map work cited earlier, suggests that NC 132 actually did have billet-to-billet variability after all. Other investigators have commented on variability between and within billets, but often furnished no concrete data or stated that the variation could not be correlated with any observable microstructural variations or inhomogeneities." " ... [Pg.556]

Microstructure variation in polybutadiene microstructure (vinyl, cis and tram). [Pg.3]


See other pages where Microstructural variation is mentioned: [Pg.303]    [Pg.61]    [Pg.264]    [Pg.344]    [Pg.347]    [Pg.119]    [Pg.267]    [Pg.157]    [Pg.72]    [Pg.902]    [Pg.9]    [Pg.241]    [Pg.242]    [Pg.334]    [Pg.293]    [Pg.25]    [Pg.267]    [Pg.166]    [Pg.157]    [Pg.291]    [Pg.370]    [Pg.227]    [Pg.204]    [Pg.572]    [Pg.445]    [Pg.518]    [Pg.451]    [Pg.270]    [Pg.185]    [Pg.31]   
See also in sourсe #XX -- [ Pg.209 ]




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