Weight uptake

Type of fiber(heat treatment) Experi- mental conditions Weight uptake (%) Elemental X-ray analysis [() minor component] Lc (after interc.) ... 

Figure 1 Shows the weight % uptake of H2 by a 35 nanogram samarium sample measured with a quartz gravimeter.

Figure 2 The weight % uptake of H2 in an ethylene complex formed from Ti is shown along with the data from Zn.

Of the samples reported here, PMMA showed the greatest uptake of carbon dioxide, while PETG and PET showed progressively lesser amounts when evaluated approximately two hours after treatment (Tables 6, 7 and 8). PET showed less than 1 weight % uptake of carbon dioxide due to the semicrystalline nature of the material. The small uptake in PET is likely due to the dissolution of the carbon dioxide in the amorphous regions of the sample. Compared with PETG, PMMA has a relatively high amount of COj... 

Several methods allowing the determination of adsorption isotherms exist. The most economical one is the use of saturated salt solutions, generating known water partial pressures, followed by the measurement of the silica weight uptake. However, the time needed to obtain a suitable adsorption isotherm is excessively long (several weeks), and experimental precautions need to be taken to achieve meaningful results. Specialized equipments, quite expensive ones, have been developed for the water adsorption isotherm determination, based on highly sensitive microbalances. 

Silicon Oxide Solids Untake. In Figure 2 are plotted percent dried weight uptake of the membranes vs. immersion time for the four solvents. The... 

Si Solid State NMR Spectroscopy. Si NMR spectra for microcomposite samples having the indicated solids percent weight uptakes affected according to procedure A (methanol solvent) are shown in Figure 10. 

Figure 10. Si solid state NMR spectra of Nafion/silicon oxide microcomposites having indicated percent dried weight uptakes firom TEOS/methanol solutions using procedure A. The diemical shifts assigned to 2-, 3- and 4- coor

Table I lists the experimentally measured dielectric constants at 0% and 40% RH, polymer densities, and the weight uptake of water per 100 g film at 40% RH for all the samples investigated. The polarizability of the absorbed water in the films was calculated using the Clausius-Mossotti equation (Equation 1) which relates macroscopic dielectric constant to molecular polarizability as follows ...

The number of water dipoles per unit volume (N ) is calculated from the weight uptake water by... 

Fickian diffusion and first order relaxation rate process. These two processes are linked through a coupling constant, 2 - D/0R The quantity 0D = L2/4D is the characteristic time for diffusion. The quantity 0 = l/kR, where kR is the first order relaxation rate constant, is the characteristic time for relaxation. The fractional weight uptake is give by the following equation ... 

Figure 15.16 Weight uptake (%) of motor oil for NR/EPDM vulcanizates versus the exposure time at 100°C and 35% compression. (From Reference 81 with permission from John Wiley Sons.)...

Figure 16.7. First-order plot of the initial weight uptake of oxygen into a 7 micron thick film of Durham polyacetylene at SO C unstablized film film containing 5% Irganox 1010. Adapted from Polym. Deg. Stab. 19, 323 (1987), permission of Elsevier Science Ltd., Kidlington.

Figure 16.9. Arrhenius plot for initial weight uptake of oxygen into polyacetylene O unstabilized Durham polymer stablized...

The formulas given in Table 1 are based solely on weight uptake data after exposure of the polyacetylene films to metal-ammonia solutions followed by washing and vacuum drying. To determine the actual metal content of the doped polymers atomic absorption measurements were carried out. These show conclusively that ammonia molecules are coinserted in the polyacetylene films along with the metal cations. This can be compared to the coinsertion of the solvent tetrahydrofuran which has been found to coordinate with the alkali metal ions Li and Na (22,23). The sodium doped samples coinsert slightly more than about one ammonia molecule for each sodium ion. The real formula for the sodium... 

Measurements on the transport of iodine in polyacetylene have been investigated by weight-uptake and electrochemical methods, but because of the uncertainties relating to the proposed structures of the iodine-doped lattice/ it has proved difficult to simulate a stable lattice consistent with the various proposed structures. ... 

Several analytical methods are used in studies of plasticizer diffusion weight uptake glass transition temperature infrared imaging sorption kinetics ... 

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