Static Characterization

Low-power or high-frequency ultrasound was used to characterize polymer blends by indirect contact with the polymers. According to the measuring state, the applications of high-frequency ultrasound can be described as either static characterization (static method) or in-line monitoring (dynamic method). 

Various sophisticated instrumental methods have been developed to characterize polymer blends and compatibility, including thermal, microscopy, spectroscopy and other processing techniques. Recently, ultrasound has also been applied extensively to the study of polymer blend properties in both solutions and solids. The ultrasonic velocity and attenuation by the interaction of the propagating wave were used to investigate the various physical properties of the polymer blends, including density, compatibility, molecular orientation, and phase inversion. 

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Such an expansion was employed by many in the early 1980s [21-27]. It is, however, of little routine use for the static characterization of polymeric monolayers since accurate measurements of surface pressure in this surface... 

Experimentally, good solvent conditions have been observed [22,23,27,28, 34,35]. On the other hand, none has been reported for the prediction of the theta condition, y = 101, whereas the prediction of poor solvent conditions giving rise to y > 3 has been reported. These all have y < 20 except for two they are poly(methyl acrylate) at lower temperatures [34] and poly(dimethyl siloxane) [24]. Others have failed to reproduce them since. A caveat needs to be raised with these results. Since the semi-dilute regime is so narrow in r before the collapse state sets in whereby the power exponent is commonly deduced for a r range less than one full decade hence, the r scaling is at best qualitative in the static characterization. 

C. Guizard, C. Mouchet, R. Vacassy, A. Julbe and A. Ayral, Zirconia nanofiltration membranes I. Mechanism of pore formation and static characterization., in preparation. 

Applications of metal NMR are no longer limited to static characterization in terms of sample homogeneity or trends in chemical shift. Examples are drawn to emphasize structural characterization and dynamic studies. A novel sapphire NMR tube is described which permits routine high resolution operation up to 2,000 psi. The tubes can be used in any spectrometer, and have allowed the study of fundamental reactions of transition metal carbonyl complexes under conditions which would otherwise bring about sample decomposition. 

Kirkwood, K. M., et al. Yarn Pullout As a Mechanism for Dissipating Ballistic Impact energy in Kevlar KM-2 Fabric, Part 1 Quasi Static Characterization of Yam Pullout. Tex. Res. J., 74, 920-928 (2004). 

Kirkwood KM, Wetzel ED, Kirkwood JE. Yam pull-out as a mechanism for dissipating baUistic impact energy in Kevlar KM-2 fabric. Part 1 Quasi-static characterization of yam puU-out. Text Res J 2004 74 920-8. 

Two categories of methods are commonly used for organic and hybrid membrane characterization. The first ones, named static characterizations, are aimed at the description of the structure and texture of membranes while the second ones named dynamic characterizations describe membranes at work, in other words the transfer of fluids and solutes through the membrane top-layer. Both static an dynamic characterization methods are important for a thorough understanding of single mass transport and even of the additional functions of the membranes (contactor, reactor...). 

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