Chemical finishing processes

An important chemical finishing process for cotton fabrics is that of mercerization, which improves strength, luster, and dye receptivity. Mercerization iavolves brief exposure of the fabric under tension to concentrated (20—25 wt %) NaOH solution (14). In this treatment, the cotton fibers become more circular ia cross-section and smoother ia surface appearance, which iacreases their luster. At the molecular level, mercerization causes a decrease ia the degree of crystallinity and a transformation of the cellulose crystal form. These fine stmctural changes iacrease the moisture and dye absorption properties of the fiber. Biopolishing is a relatively new treatment of cotton fabrics, involving ceUulase enzymes, to produce special surface effects (15). 

Natural fibers may be adversely affected by sunlight, air pollutants, acids and alkali, bleaches and other oxidizing agents, and chemical finishing processes. However, the effects of photochemical degradation are by far the most problematic in the conservation of textiles and therefore have received the most attention. 

The first application of a drum granulator for fertilizer agglomeration was reported to have taken place in 1935 in Baltimore, Md., USA. 9 Great advances were made in the 1950s when the continuous ammoniator , in which both a chemical finishing process and granulation occur, was introduced by the Tennessee Valley Authority in the USA. ... 

Surface modification/treatment of textile materials by chemical finishing processes is not environmentally friendly, as a result of which an alternative technology, laser irradiation has been widely adopted. By using laser irradiation, the textile materials can be structurally modified and their surface can be functionalized and textured. Here, two different examples of textile materials are presented and discussed in terms of laser treatment cotton,... 

Table 9.2 briefly explains some chemical finishing processes and their effects on characteristics of goods. 

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