Ni-H/sub 2/ improvements by use of fibrous nickel electrodes
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The behavior of fibrous nickel electrodes working in Ni-H/sub 2/ batteries has been studied in order to lighten these cells. The characteristics of the electrodes have been chosen taking into account the fact that a compromise between the swelling of electrodes and their capacity had to be defined. Cycling tests in accelerated geostationary mode are reported with this type of cell; 900 cycles have already been obtained without any decrease in performance. The end of discharge cell voltage is practically constant and a capacity equal to approximately 90% of the nominal capacity is recovered.< Abstract A NUMBER of references have already been made to the swelling of rubbers by organic liquids and to the effects of such swelling on their mechanical properties. The nature of the swelling process in itself, and the factors which determine the degree of swelling attained in any particular circumstances, have not, however, yet been considered. The property of swelling in suitable low-molecular-weight liquids is one which is possessed by a wide range of high polymers, both natural and synthetic. In many respects this property is akin to solution, and, as in the case of solution, it is markedly dependent on the nature of the swelling liquid.
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Swelling capacity
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Abstract A study of the swelling of Acala 4‐42 cotton in aqueous alkalis and acids has been carried out. The degree of swelling of the cotton in the reagents has been indicated by measurement of the variations in width of the cotton at its widest point. The nature of the swelling process whether interfibrillar or intrafibrillar has been deduced from microscopical and x‐ray evidence. It has been shown that a similarity of shape of the swelling curves, i.e., an equal degree of swelling in the same or other reagents, does not imply the same mechanism of swelling. The results are more readily explained in terms of the crystalline‐fibril theory than by the fringe‐micellar theory, especially when high degrees of swelling have been achieved.
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The mechanism of the interfibrillar and intrafibrillar swelling of cotton has been investigated by infrared and x-ray methods. Emphasis is on swelling in caustic soda, but other reagents are also considered. The presence of intrafibrillar swelling can be shown by detection of intermediate complex formation, while the swelling agents are present. The swelling behavior and the structural changes produced in the cotton are modified by the effects of tension and also by the presence of additives in the swelling solution. Whether the swelling complexes are intermediate in the conversion of cellulose I to cellulose II, or a reconversion to cellulose I results on washing out the swelling agent and drying, depends on the degree of swelling at different stages of the process. Intrafibrillar swelling is usually accompanied by an increase in the hydrogen-bond disorder, even if reconversion to cellulose I takes place, and the detection of this increase in disorder by ir-deuteration methods may be the only indication of an intrafibrillar swelling process. An explanation of the observed behavior is put forward in terms of the concept of cellulose sheets. The ideas developed from a study of the swelling of cotton by caustic soda and other swelling agents have been used in explaining the effects found in the mercerization and other finishing processes applied to cotton.
Caustic (mathematics)
Swelling capacity
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A new anti-swelling agent was synthesized by polymerizing epichlorohydrin and dimethyl amine polymer. The swelling inhibition properties were investigated over clay and shale. It was found that the clay inhibition of swelling properties was greatly enhanced compared with common inorganic salts. However, to shale, the swelling properties did not inhibited efficiently by using prepared polymers. Furthermore, the influence of cross linking of polyammonium to the swelling ability of prepared polymer has been also carried out by using triethylenetetramine cross linking agent. In the case of shale, the swelling inhibit properties was improved after cross link, while opposite swelling effect was observed over clay.
Epichlorohydrin
Triethylenetetramine
Swelling capacity
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Abstract The swelling behavior of poly( N, N '‐bisphenoxyphenylpyromellitimide) (PMDA‐ODA) using dimethylsulfoxide DMSO and N ‐methylpyrollidinone NMP was investigated by gravimetric means. For PMDA‐ODA samples imidized on a substrate, the weight uptake was found to depend linearly on time over a temperature range from 25 to 150°C. For a given temperature of imidization, the equilibrium swelling concentration was found to be independent of the temperature at which the swelling studies were performed. However, the rate of solvent uptake depended strongly on the swelling temperature, yielding an activation energy of about 50 kJ/mol. In general, increasing the initial imidization temperature caused a decrease in the rate of swelling but did not alter the equilibrium swelling concentration. This swelling behavior resembles Case II diffusion typically seen in glassy polymers with some noteworthy exceptions. In cases, where PMDA‐ODA was imidized in a free‐standing state, no swelling was observed. However, deformation of these isotropic specimens was found to induce substantial swelling.
Gravimetric analysis
Atmospheric temperature range
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In this paper,by means of confined free swelling test and confined swelling test under loads,redbed mudstone of Shaximiao group in the Middle Jurassic in Chongqing area is present to study its swelling characteristics under confined free and loading conditions,and swelling under different water injections as well.Results reveal that three phases are present in the confined free swelling of mudstone,fast swelling deformation and high swelling increasment in the first phase and increasing swelling velocity in the second phase.95 percent swelling occurs in the former two phases.It is found that vertical loads greatly restrain the confined swelling of mudstone.The confined loading swelling ratios decrease sharply with the increasing vertical loads.Moreover,the amount of water has no obvious effect on swelling characteristic of red bed mudstone within a short time under confined without load,but it plays a controlling role on the stable swelling capacities,swelling processes and characteristics as time lapsing.
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It is inexact to speak of "swelling clays" and "nonswelling clays." The highly swelling clays and the poorly swelling clays are merely end members of a continuous natural range. Identification of a clay as a montmorillonite does not tell whether it is a highly swelling or a poorly swelling clay. Lattice expanding ability as observed in the usual X-ray test is not directly related to macroscopic swelling ability; and swelling ability cannot be predicted from such an X-ray test. Swelling ability cannot be predicted from chemical analysis or particle size analysis. At the present time, the only reliable way to identify a clay as a highly swelling or poorly swelling clay is to perform a swelling test on it.
Swelling capacity
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Acrylic acid
Swelling capacity
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