Page 44 - New Cloth Market November 2022 Digital Edition

Chitosan-Based Sustainable Textile Technology: Process, Mechanism, Innovation & Safety

Ramadan et al. [56] regarding dyeing the process, the fabric is rinsed with Furthermore, a share thinning property
treatment of chitosan-treated cotton water for several times and treated with is exhibited by chitosan solution when
fabrics. A cotton fabric is immersed in 1% wetting agent using a liquor ratio the viscosity is measured. Besides, the
an aqueous solution of 2% chitosan of 1:50 for half an hour at 60°C. Several viscosity is lower than commercial
and 50 mg/100 ml sodium periodate washes are required using hot and Alcoprint pastes (BASF) when the
(NaIO4). The liquor ratio is maintained normal water after the treatment and share rate is less than 50 per s. In
at 1:50 for 60 min when the dye bath dried at room temperature. The contrast, almost similar viscosity
temperature is kept constant at 60°C. enhanced color yield (K/S) is observed profile is found at higher share rate,
The treated cotton fiber is washed with compared to the untreated fabric due but yield point is lower than the
1% aqueous acetic acid solution and to the Coulombic attractions between commercial paste. It indicates that the
rinsed with water for several times, and positively charged cotton surface required force or stress of the chitosan
the drying temperature was maintained modified by chitosan and anionic dye to start flowing is very low. Besides,
at 60°C. molecules (reactive and acid). the wet pick-up ratio of chitosan
solution is 75%, while the commercial
Two steps are followed for the fabric Chitosan: a binder in printing paste shows 85%. It results in 50%
treatment with chitosan to compare the process less color strength using chitosan
dyeing and mechanical properties of solution after the determination of K/S
the treated fabrics. The underlying Fabric printing process requires a dye values. It probably attributes to the
mechanism of the process is to create or a pigment, a binder and thickener. aggregation of colorant in the chitosan
aldehyde groups in the molecular The main function of binder is to solution where the dispersion is tough
structure of chitosan at C1 through the maintain a stable viscosity, enhances to maintain. In addition, the bending
action of NaIO4. In addition, C3 and the droplet formation, provides length and stiffness are higher for
C4 positions hold secondary hydroxyl adequate adhesion to the textile chitosan-used printed fabric compared
groups; position C6 contains primary surface by forming a film, and binds to Alcoprint pastes, the commercial
hydroxyl and C2 holds the amino the color or pigment molecules. In the one. Eventually, the wash fastness and
groups. Moreover, the chain scission industrial application, most of the spreading behavior are not significantly
occurs at C3, C6, C2 positions and 1– binders are synthesized from styrene- different between chitosan and
4 glycosidic linkage under the attack butadiene, or vinyl acetate-acrylate commercial tested binders [59].
of oxidizer [57]. The IR analysis copolymers or styrene-acrylate. Very
confirms the presence of aldehyde and few researchers have conducted Chitosan: a finishing agent for
carboxyl groups in the molecular experiments on using chitosan as durable press for textile
structure of treated cotton, which binder and thickener due the weak
interacts with chitosan strongly. There performance compared to commercial The cotton fabric is hydrophilic due to
is a possibility to degrade the fabrics binders. In the first step of preparation, a high amount of hydroxyl groups.
due to oxidizing, but the presence of 3% (w/w) chitosan solution is prepared Therefore, the cotton cellulose
chitosan may reduce this drawback. using preferred amount of water and becomes flexible and exhibits lower
acetic acid. The pigment is added to crystallinity when it is swelled. A plastic
The presence of chitosan also protects the solution and stirred to achieve a deformation occurs due to the shifting
the fabric from degradation against the 3% homogeneous pigment paste for of cellulose molecules during washing
attack of the oxidizer and maintains printing. In the case of poor dispersion treatment. It results in shrinkage and
similar mechanical properties (i.e., of pigments, the amount of acetic acid wrinkles of fabric. For overcoming the
tensile strength, elongation at break) is increased. Additionally, a very high problem, the crosslinking agent is used
to the untreated bleached fabric [56]. amount of chitosan (=3%) in acetic to increase the elasticity and prevent
In addition, highly soluble, uniform acid generates very highly viscose the displacement of cellulose which
structure, low viscous, and better film- solution. The achieved properties of the reverses the plastic deformation.
forming chitosan is achieved from the process exhibit lower efficiency and Chitosan exhibits similar molecular
fragmented chitosan [58]. effectiveness of chitosan as a binder structure to cellulose and would be
compared to the commercial Alcoprint applied to cotton finish. During this
In the second step, the dyeing process pastes (BASF). The tendency of process, chitosan is fragmented by
is conducted using the dried cotton yellowing is higher after the treatment oxidizing agent such as hydrogen
fabric in 1% reactive dyes while 5% with increased amount of chitosan and peroxide (H2O2). The fragmentation
sodium chloride in a liquor ratio of 1:50 the increase of the curing temperature. process is carried out using a mixture
at room temperature. The temperature Moreover, same process parameters of hydrochloric acid and chitosan. After
of the dye bath is increased at 60°C in different batches show variation in 30 min of stirring, hydrogen peroxide
and left it to be stable for 45 min. After yellowing propensity. is added with an increased temperature

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