Textile surface structuring processes

Textile surface structuring processes, which are basically classified as weaving, knitting, and nonwoven, vary based on their processing steps and machinery types. They are mostly dry operations and mostly consume electric energy for machine driving and air conditioning purposes. 

An important parameter influencing the mode of action of cellulases is the accessibility of the cellulose to the enzymes. The molecular weights of cellulases range between 30 and 80 kDa. A comparison of the size of cellulase (3-8 nm) and the pore size of cotton swollen in water (1-7 nm) shows very clearly that cellulases can penetrate the cellulose to a limited extent only. In addition, the enzyme reaction takes place preferentially on amorphous cellulose because the more compact, crystalline cellulose structures do not offer any space for such macromolecules. Thus - provided of enzyme and process parameters have been selected correctly -cellulases act mainly on the textile surface. In this way interesting effects on cellu-losic fibers can be achieved. 

Continuous coating is a well-established process in the non-woven industry. Non-woven textiles reach their final product quality tensile strength, resistance against humidity or surface structure only after the application of appropriate additives to the surface or interior of the textile. In principle, a number of methods are convenient, as shown in Figure 4.107 [167]. 

The 3D structure between two textile surfaces can be produced with the flock technology. In this technology, short cut fibres (flock fibres) are electrostatically charged and applied on adhesive coated substrate using an electric field. The flock technology is over 100 years old and is used in various technical, medical and textile sectors. The so-called filter-flock method is a process to improve the characteristics of spacer fabrics. The ribs made with flock, also known as rib-flock , allow for a greater conduction of excess heat and body moisture from the body due to their channel-shaped structure (cf. Section 14.3 Krel et ah, 2005 Machova et ah, 2006). 

The process of integrating the textile surfaces onto a polymer substrate is depicted in Figure 10.5 for a microstrip transmission line (TL) structure (Zhang et al., 2012). Embroidered TLs and ground planes were first laminated with PDMS. Then, the two PDMS sides were joined using an extra-thin layer of uncured PDMS (Wang et al., 2012b). 

From the preceding description of the structure of polymers in fibers, the mechanical and thermal stresses that are applied during manufacturing, texturing or textile fabric production, the additives that are deposited onto the surface during processing or with the purpose of introducing specific behavior in the final fiber, yam or textile, it is clear... 

There are large differences in quality between different porous materials depending on structure and type of material. A porous material such as textiles can be hydrophilic or hydrophobic. The hydrophilic fibers can absorb water, while hydrophobic fibers do not. A textile that transports water through its porous structures without absorbing moisture is preferable to use as a first layer. Mass transfer during drying depends on the transport within the fiber and fi om the textile surface, as well as on how the textile absorbs water, all of which will affect the drying process. 

Figure 12.17 shows the formation process of such a pill. In the beginning, single fibers are more or less dragged out of the textile (a, b). Then after further friction is applied, the fiber ends form loops (c). Cloud-like fiber agglomerations are formed (d), and finally, the fibers can form knot-like structures (e). This knot is connected to the textile surface by a single fiber, the so-called anchor fiber. 

The result is a fiber that is less crystalline and dyes more readily. The downside is an unavoidable reduction in transition temperatures, a less stable structure more prone to shrinkage, and the easier escape of dye molecules and oligomers which can deposit onto the surfaces of textile processing equipment. Depending on the level and type of comonomer used, increased problems with lightfastness or polymer degradation can also occur. 

While some of the Mississippian textiles are of similar structure to the Middle Woodland textiles, others are very complex materials and are lace-like in appearance. Many of the materials from Etowah are preserved by mineralization, and display green-colored deposits on their surfaces. Bast fiber, rabbit hair, and feathers have been identified (2, 11). The textiles from these two sites selected for analysis are representative of the complexity of structure and fineness of yarns seen in the materials they provide evidence of the sophisticated technology of prehistoric people in all phases of fiber collection, processing, yarn spinning, fabric manufacture and, when present, coloration. 

A possible explanation for this effect can be found in the 3D structure of textile electrodes and its permeability for liquids. While slowly soaking electrolyte solution, the contact surface between textile electrode and electrolyte increases. The latter effect gives rise to a decrease in the resistance because of a larger value for A. As this process is occurring reasonably... 

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