Fiber sorption properties

Fiber sorption properties mainly determine the evaporation process and therefore the heat and mass transfer by evaporation of water, diffusion of water vapor, and condensation. Water evaporates from hot regions and moves across the gas-filled pores by diffusion and condenses on the cold region, thus releasing its latent heat of vaporization [19—21]. 

Clemons, C., Young, R.A. and Rowell, R.M. (1992). Moisture sorption properties of composite boards from esterified aspen fiber. Wood and Fiber Science, 24(3), 353-363. 

Rowell, R.M. and Rowell, J.S. (1989). Moisture sorption properties of acetylated lignocellulosic fibers. In Cellulose and Wood Chemistry and Technology, Proceedings of the 10th Cellulose Conference, Schuerch, C. (Ed.). John Wiley Sons, Inc., New York, pp. 343-355. 

Sorption equilibria and kinetics are influenced by the nature of the adsorbent and the adsorbate, by the mechanism of adsorption, and by environmental parameters such as temperature, relative humidity, concentration of the adsorbate, and air velocity and turbulence past the adsorbent surface. Air velocity and turbulence only affect sorption kinetics the other parameters also affect equilibria. In general, low adsorbate saturation vapor pressure, low temperature, and high adsorbate concentration in the air increase adsorption. Relative humidity does not always affect adsorption. Colombo et al. (1993) found a 35 % decrease in adsorbed mass when relative humidity was changed from <10 % to 35 %, but only an 8 % decrease when the humidity was increased from 35 % to 70 %. Building materials, which are exposed to indoor air in the normal humidity range of 35-70 %, will typically already be covered by at least one monolayer of adsorbed water, and the formation of multilayers will only have a limited influence on sorption properties for other airborne substances. Kirchner et al. (1997) found that an increase in air velocity increased the rate of desorption of a VOC mixture from painted gypsum, but not from carpet. The air velocity of air above the tuft may be insignificant for the desorption processes of carpet fibers deeper in the tuft. 

Chvalinova, R., Wiener, J., 2008. Sorption properties of wool fibers after plasma treatment. Chem. List. 102, sl473-sl477. 

European Parliament (2000) Council Directive 2000/53/EC of 18 September 2000 on end-of life vehicles, http //eur-lex.europa.eu/en/index.htm. Accessed 20 April 2010 Fakin D, Golob V, Kleinschek K, Le Marechal A (2006) Sorption properties of flax fibers depending on pretreatment processes and their environmental impact. Text Res J 76(6) 448-454... 

Demir H, Atikler U, Balkose D, Tihmmhoglu D (2006) The effect of fiber surface treatments on the tensile and water sorption properties of polypropylene-luffa fiber composites. Compos A 37 447 56... 

Keywords bicomponent fiber, multicomponent fiber, fibers of noncircular cross-section, sorption properties, separation, bioactive fibers, filled fibers, antibacterial textiles. 

Since the thermal resistance of air is higher than fibers, fiber has little influence on fabric thermal resistance, therefore insulated properties of fabric in a dry state. When a fabric becomes wet, the role of fiber on thermal resistance may become more important because of the low thermal resistance of wato-. As water saturates inte-yam spaces, air in these spaces is displaced, reducing the contribution of air and increasing the contribution of moisture transport of the fibers to the thermal resistance of a fabric. The thermal conductivity of wet fabrics is increased with increased moisture content. The sorption properties of a particular fibo", ie, hydrophihc and hydrophobic, influence the rapid thermal conductivity increase at the initial stage thereafter the increase of thermal conductivity with increasing wato" content behaves similarly for all fibo" types [25—27]. 

Water vapor is the main sorbate used for the study of the sorption properties and structure of various cellulose materials such as cellulose powders, films, and fibers of regenerated cellulose, textile materials, pulp, paper, cardboard, and some other materials. Sorption of vapors is usually described through isotherms having various shapes that express the relative amount of sorbate in the sorbent A, g/g) as a function of relative vapor pressure (

constant temperature (Gregg et al., 1982]. To calculate sorption parameters and structural characteristics of sorbents, the obtained isotherms should be linearized by the appropriate equations corresponding to the assumed sorption mechanism. 

Enzymes are used to improve sorption properties of cellulose fibers, to increase specific area and volume of fibers, to remove pectin companions of cotton and linen cellulose. Enzymes also hydrolyze ether bonds on the surface of polyether fibers. 

Composites made from lignocellulosic materials have been restricted from many markets because of their moisture sorption, dimensional instability, and to a lesser extent, biological degradation. These negative properties can be overcome, allowing flakes, particles, and fiber from wood and agricultural residues to find markets related to high-performance composites. 

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