Wool fiber surface properties

Makinson, K. R., Surface Properties of Wool Fibers, Surface Charac-... 

As discussed above, increases in wettability have been one of the primary and well-recognized surface effects obtained on textiles with plasma systems which utilize oxygen, air, and ammonia plasmas. Other recognized benefits are enhancements in surface desizing and capillarity of natural textile fibers such as wool and cotton. Particular to the hydrophobic properties of wool fiber surfaces, we have summarized that these can be transitioned to hydrophilic to obtain a reduced felting effect. However, if there is interest in moving toward an inverse effect, hydrophobic properties, as observed on cotton fabrics, can be also induced with prescriptions of type and proportions of gas chemistries used in the plasma reaction [33]. 

Following early ETEM investigations using environmental cells, environmental scanning electron microscopy (ESEM) has been developed for characterization of surface effects of bulk SEM samples in the presence of gaseous or wet environments (111-114). The method has been applied to the examination of food, wool fibers (111), and polymers (112) and in the conservation of cultural properties (113). Recently, fuel cell catalysts have been characterized using a low-voltage ESEM with a resolution capability of 2 nm (114). 

Oxidation of the surface of wool fibers is known to reduce felting shrinkage as well as improve other properties of wool fibers (37) Oxidation may be proformed or effected in a number of ways including gas phase plasma treatment (38). 

Summary Silanes are used as additives in numerous examples of resin chemistry. From these progresses in two applications, mineral wool production and paper impregnation, are highlighted. In the first application, silane acts as a typical coupling agent to improve the binding between resin and fiber, whereas in the latter, silane functions as a modifier to improve surface properties of the final laminate. 

Interfacial and solution polycondensations are commercially important. For example, an unstirred interfacial poly condensation reaction is utilized in the production of polyamide fibers. Another important application of interfacial polycondensation is the enhancement of shrink resistance of wool. The wool is immersed first in a solution containing one of the reactants and subsequently in another solution containing the other reactant. The polymer resulting from the interfacial reaction coats the wool and improves its surface properties. 

Flattened cuticle cells primarily account for most of the surface properties of mammalian fibers. In Merino wool, cuticle cells are approximately 20 xm x 30 xm x 0.7 xm [35]. Cuticle cells overlap both longitudinally and circumferentially with exposed lips or scale edges pointing toward the distal end of the fiber. The scale edges are thought to aid in the removal of dirt and vegetable matter, but they may also assist in anchoring the fiber to the skin [36]. 

Research on plasma treatment on wool fiber as a pretreatment was started in 1956 (Rakowski, 1997). Plasma-treated wool fiber displays improved antifelting property, dye-ability, and surface wettability. The plasma treatment can alter the surface morphology and chemical composition, but the effect depends greatly on the plasma gas used, system pressure, discharge power, and also treatment lime. Plasma treatment on wool fiber is a dry process in which fiber alteralion is concentrated on the fiber surface and less damage is caused to the bulk fiber. This is a major advantage of plasma treatment on wool fiber. 

Then, the rating values were correlated with statistical values, so-called fabric hands, (secondary performance) such as stiffness, fullness or flexibility of clothes. Finally, the values of fabric hands were compared with other empirical values, e.g., mechanical properties and surface characters of fibers (primary performance). He succeeded in obtaining excellent suits fabricated with polyester fibers, instead of wool fibers, by using the "Experimentel1e Aesthetic"- ike methods (but with more delicate processes). 

Sinha E, Panigrahi S (2009) Effect of plasma treatment on structure. Wettability of jute fiber and flexural strength of its composite. J Compos Mater 43(17) 1791-1802 Kan CW et al (1998) Surface properties of low-temperature plasma treated wool fabrics. J Mater Process Technol 83(1-3) 180-184... 

Properties of fibers can be altered by carrying out interfacial polymerizations on their surfaces. Thus the shrink resistance of wool can be improved by immersing the fiber first in a solution containing one component of a condensation polymer and then immersing it in another solution containing theother component. Polyamides, polyurethanes, polyureas, and other polymers and copolymers may be grafted on wool in this manner. 

Through plasma treatment, grafing of monomers can also take place on the polymer surface. For example, monomers, e.g., tetrafluoroethylene or hexafluoroethane, can be grafted onto wool or polypropylene fibers ( ). This type of grafting can improve such tribological properties as low friction. 

In the mature fiber, cuticle cells essentially perform a protective function however, they also play an important role in controlling the ingress of water and other chemical substances [16,41]. Hence a detailed understanding of the cuticle strueture and reactivity is essential to provide a basis for improving many of the textile properties of wool and other fibers. The nature of the fiber cuticle surface in particular is a high priority of current research activities. 

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