Textile fiber water content

The fine structure and morphology of nylon-6 are significantly influenced by the equilibrium water content as a time-induced phenomenon. The interaction between process and water content is illustrated with the packaging behavior of nylon-6 carpet and textile fibers with molecular weight of 55-60 FAV ... 

CAS 5205-93-6 EINECS/ELINCS 226-002-3 Uses Adhesion promoter, mfg. of quats, improves dyeability of textile fibers, photopolymer plates, photoresists, paint resins and emulsions, oil additives, electro dipcoats, rubber modifiers, dental compds. Properties Pt-Co 50 max. clear liq. ester-like odor m.w. 170 sp.gr. 0.94 vise. 28 cps (20 C) b.p. 134 C flash pt. 140 C ref. index 1.478 (20 C) 98.5% min. purity 0.1% water content Toxicology TSCA listed Storage 3 mos shelf life 30 C max. 

Table 14.7.1. Water content (%) in textile fibers dependent on relative humidity...

As mentioned above, heat and mass transfer in textile materials is a complex phenomenon that includes several mechanisms. Textile material properties significantly influence these mechanisms. Several researchers studied the effect of these properties on heat and mass transfers at three different levels (1) the microscopic level (chemical composition, morphological characteristics, fineness, cross-section, porosity, and water content of the component fibers), (2) the mesoscopic level (yam structure and properties), and (3) the macroscopic level (the fabric s physical and stmctural characteristics and finishing treatments) [3,22,23]. Thus, in the following section, heat transfer properties, such as thermal conductivity, thermal resistance, thermal absorptivity, and thermal emissivity and mass transfer properties, such as water vapor transmission and liquid water transmission, will be defined at fiber, yam, and fabric levels. 

The ability of a textile fiber to absorb water from the atmosphere is important in many applications. In addition to the chemical and physical structures of the fiber, the temperature and water content of the atmosphere strongly influence the amount of water that is absorbed by the fiber. In this respect, a standard atmosphere is defined as air maintained at 20 °C and 65% relative humidity. Special humidity and temperature conditions are sometimes prescribed for the testing of textiles for specific purposes. The test specimens are often brought to moisture equilibrium in the standard atmosphere before tests are carried out. 

TABLE 1 Smoothed values of dry-basis moisture content (kg/kg) for the adsorption of water vapor at 30°C onto textile fibers. 

Wiersma et al. at DSM Research, Geleen, The Netherlands [284] described an interesting way of coating textile fibers with CP/polyurethane and CP/alkyd blends from aqueous colloidal dispersions made in a commercially available aqueous resin dispersions. The dispersions included a polyurethane-in-water dispersion (DSM Resins URAFLEX XP 401 UZ, 40% solids content). A variant of the template-type in-situ polymerization was used. After polymerization, the dispersed CP sol could be applied as a coating onto the textile fibers. CPs used included P(Py) and P(ANi). 

The moisture absorption/desorption capability of the solid fiber depends on the relative humidity of the enclosed air in the microclimate around the fiber and the type of fiber material. When fibers absorb moisture, heat is generated and released. Consequently, the temperature of fiber will rise and thus results in an increase of dry heat flow and a decrease in latent heat flow across the fabric [11]. The absorbed/desorbed moisture of fibers and the water vapor in the enclosed microclimate in textiles compose the water content of the textile material, which can originate from the... 

Fan and Luo [12] incorporated the new two-stage moisture sorption/ desorption model of fibers into the dynamic heat and moisture transfer model for porous clothing assemblies. They considered the radiation heat transfer and the efFect of water content of fibers on the thermal conductivity of fiber material. Further, Fan and his co-woricers improved the model by introducing moisture bulk flow, which was caused by the vapor-pressure gradients and supersaturation state [12]. This improvement made up for the ignorance of liquid water diffusion in the porous textile material in previous models. The equations of the model are listed as follows ... 

Specific Heat. The specific heat of textiles, particularly wool, has been the subject of recent investigations. For moisture contents above the fiber saturation point of wool, reduced, supercontracted, and chemically modified wool fabrics exhibited endothermic peaks at -30 to 0°C that resulted from the heat of fusion of absorbed water. In that temperature range, a significant increase in the specific heat of the wool fabrics was also... 

The textile processing oils are generally oil-soluble or water-dispersible fatty materials which are used to provide either lubrication of fiber surfaces or higher moisture content, or both. 

This moisture content has been shewn to result In a marked lowering of the T for many fibers. Further reductions In T occur when the flblr Is allowed to wet out In water until equilibrium saturation Is reached. These lowered T s are of significance In the processing and care of textile products. Several methods particularly useful for measuring the wet and dry T of fibers... 

One of the most thoroughly researched applications of NIR to textile substrates is the measurement of substrate moisture content. Most of the textile moisture applications are for natural fiber products — wool, cotton, and so forth. For synthetic textile products, Elliott and coworkers [32] studied the spectral locations and the spectral influence of water on synthetic fiber spectra. Rodgers [17,33] measured the moisture content of nylon fibers by NIR spectroscopy both in the laboratory and at-line/ pseudo on-line. 

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