Absorption behavior applications

Dyes with similar absorptive behavior should be selected for combined application. The combination values for acid dyes established originally for polyamide were later transferred to wool [86, 87],... 

Agro-based fiber-reinforced composites can absorb a significant amount of moisture, as the water retains in the inter-fibrillar spaces of these fibers [10]. The content of voids and the non-crystalline parts determine moisture absorption [3]. When these fibers are used in composites, the moisture can occupy the spaces in the flaws of the interface between the fiber and the matrix and the micro voids in the composites in addition to the inter-fibrillar spaces of the fibers [10]. The moisture absorption behavior of plant fibers is one of the main concerns related to the utilization in composite applications [24]. The moisture absorption that takes place as a result of the hydrophilic character of the fiber affects the performance of the composite negatively. Moisture uptake results in fiber swelling and this consequently changes the dimensional stability of the... 

The possible interaction between MCNF and PMMA molecules during free radical polymerization resulted in an improved mechanical, thermal and moisture resistance property. They also prepared equivalent PMMA/cellulose nanocomposites by conventional ex-situ solution dispersion technique (MMEPC) which showed much lower properties. This observation clearly showed the benefit of in-situ polymerization technique in terms of mechanical property enhancement. It is well known that cellulose-reinforced composites show extensive moisture absorption behavior which is considered to be their major drawback when practical application possibilities are considered in the fields like packaging, coating, etc. The % moisture uptake of MMIPC was reported to be 52% lower than that observed in the equivalent ex-situ composites (MMEPC) although both contained same amount of MCNF fillers (Figure 5.14). 

Solubilities of ammonia in ionic liquids, l-ethyl-3-methylimidazolium acetate ([EMIm]Ac), l-ethyl-3-methylimidazolium thiocyanate ([EMIm]SCN), l-ethyl-3-methylimidazolium ethylsulfate ([EMImJEtOSOs), and N,N-dimethy- lethanolammonium acetate ([DMEA]Ac) were measured for the first time by A.Yokozeki and M.B. Shiflett [7] in 2007. Six mixture compositions of each binary system were involved from about 30 to 85 mole% of ammonia. Pressure-temperature-composition (P-T-x) data were claimed at isothermal conditions of 283, 298, 323, 348, and 373 K. The observed solubility of ammonia in ionic liquids is very high, and all cases show negative deviations from ideal solution behavior. Experimental P-T-x data were successfully correlated with the equation-of-state (EOS) model [8]. The experimental data and fitting results are shown in Figure 5 8. The opportunity for the absorption cycle application using the ammonia-RTIL system, replacing the traditional ammonia-water system, has been discussed [7]. 

To facilitate the research and development of aliphatic PEMs, this chapter gives a comprehensive overview of several decades of development and recent trends in the material selection, design and synthesis, characterizations, their conduction property and water absorption behavior, conduction mechanisms and chemical stability, as well as their possible applications in fuel cells, Zn-air batteries, and rechargeable Ni-MH batteries and even in carbon dioxide electroreduction. Various aliphatic PEMs explored and reported in the literature and their modification techniques are summarized. Challenges and perspectives are presented in depth with respect to membrane conductivity and stability. Some typical aliphatic PEMs and their associated data from material selection, synthesis, characterization, and applications are also summarized and presented to help readers quickly locate the information they are looking for. 

The interest of physicists in the conducting polymers, their properties and applications, has been focused on dry materials 93-94 Most of the discussions center on the conductivity of the polymers and the nature of the carriers. The current knowledge is not clear because the conducting polymers exhibit a number of metallic properties, i.e., temperature-independent behavior of a linear relation between thermopower and temperature, and a free carrier absorption typical of a metal. Nevertheless, the conductivity of these specimens is quite low (about 1 S cm"1), and increases when the temperature rises, as in semiconductors. However, polymers are not semiconductors because in inorganic semiconductors, the dopant substitutes for the host atomic sites. In conducting polymers, the dopants are not substitutional, they are part of a nonstoichiometric compound, the composition of which changes from zero up to 40-50% in... 

Again, care has to be taken for the non-ideal (or real) behavior of the measurement system. Applications are limited by non-specific absorption of molecules on the surface, mass transfer effects (under conditions of laminar flow a 1-5-pm layer between sensor surface and volume flow is not whirled and has to be passed by passive diffusion) or limited access for the immobilized molecules [158-160]. 

The absorption of moisture critically affects other important resin properties, particularly those associated with low-dielectric and thermomechanical applications. Results of a 96-h boiling water immersion test are presented in Table 2.2. The moisture absorbed decreased substantially with fluoromethylene chain length from n = 3 to n = 6, followed by only modest decreases for n = 8 and 10. This latter behavior was somewhat unexpected and may be the effect of decreased cross-link density counteracting the increased fluorine content. These 100°C measurements are just above the glass transition and the situation may be different at room temperature. These measurements are in progress. 

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