Biomedical Engineering Reference
In-Depth Information
there is also a transition part between these two regions. These different regions
in chemical reactions exhibit different reactivity. For instance, in the enzymatic
hydrolysis process, the amorphous region is the most vulnerable to damage; the
transition part is also affected, but the crystallization region is less affected.
9.1.1.1
Application of Cellulase in Modification of Cotton Fabrics
Enzyme, as a natural degraded biological agent, plays an increasingly important
role in the textile industry [
3
]. Bioprocessing of cellulose fiber and fabric is one
of the main application areas for enzymes. Cellulase, as a biological enzyme, has
experienced rapid development since introduction into the textile industry in the
1980s. The utilization of cellulase in the textile industry has the following advan-
tages: (1) as a biological catalyst, it is nontoxic and harmless; (2) it requires mild
processing conditions (temperature, pH, etc.); (3) only a low dose of cellulase is
necessary; (4) the cellulase released from one reaction can catalyze another reaction
successively; (5) wastewater generated during reactions can be biodegraded, which
can reduce pollution and conserve energy; (6) the effect of some special features
can be acquired, and the performance of fabric can be improved [
4
].
(1) Decrement and softening of fabrics with cellulase
Treating cotton textiles with cellulase would cause reduction and weight loss of
cotton fiber and changes of fiber properties, including softness, water absorption,
dyeability, drapability, smoothness, mechanical properties, and so on. The main aim
of weight reduction treatment is to improve the softness, flexibility, and drapability
of cotton fabric, making the fabric silky and causing changes in other performance.
Because the enzyme treatment may damage the mechanical properties of cotton
fibers, more attentions should be taken during the processing.
The weight loss rate of cotton fabric after cellulase treatment is related to many
factors, such as types and concentration of the enzyme, pH of the reaction solution,
temperature, processing equipment, velocity of flow, organizational structure of tex-
tiles, and pretreatment (mercerization, bleaching) conditions. In cellulase treatment,
the cotton fabric weight loss rate and various properties should be well balanced. It
is good to control the weight loss rate of cotton fabric within the range of 3-5 %.
(2) Polishing of fabrics with cellulase
Polishing, first proposed in Japan, is novel biochemical processing of fabrics. It
deals mainly with cotton fabrics to make the surface smooth and to improve softness.
Asferg and Videback extended the basic principle of polishing to knitting and other
cellulosic fabrics and found additional effects, which were the reduction of lousiness
on the surface, thus also reducing the tendency of pilling. Pederson and Sasserod
also proved the durability of the polishing effect of cellulose fabrics.
Polishing of cotton fabrics by cellulase would decrease pilling and stiffness,
increase compressibility, and improve fabric handling. Thus, the drapability of
fabrics would be improved; also, luster and color are enhanced, so the fabrics have
a silky gloss similar to that produced by traditional mercerization, and the lines of
the fabric are delicate and clear [
4
].
