Page 46 - New Cloth Market November 2022 Digital Edition

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

and silver particles both are used for requirement of mechanical properties. fabric is dipped, and a padder is used
the synthesis of chitosan-silver The raw cellulose fibers are dipped in to nip the treated fabric as though 70%
nanoparticles which provide excellent the solution and raised the temperature pick-up ratio is achieved. The predrying
antibacterial property on textile at 70°C in the pH range from 3.8 to temperature is maintained at 120°C and
application. The application of chitosan 4.1. The pH is not recommended over run for 2 min.
and its derivatives on fabric/fiber is 4.5 to perform the crosslinking reaction
followed by the covalent crosslinking and avoids fibers deterioration. The Subsequently, a curing process is done
into cellulose or wool substrates. The treatment continues for 5 min, and at 150°C for 3 min. The tensile strength
durable press finishing is one of the fibers are removed for curing at 130°C and bending length of chitosan-treated
conventional processes to fix up to 3 min. After the curing process, cotton fabric enhanced with the
chemicals on fiber surface that also the samples are dried at room increasing of chitosan concentration.
enhances the quality of textiles such temperature under vacuum, before It affects the stiffness of the treated
as low-shrinkage capacities, anti-odor, rinsing with distilled water and washing fabric by increasing the value.
wrinkle resistance, and antibacterial with acetic acid to remove the excess Moreover, chitosan-treated cotton
properties. For this purpose, a suitable unreacted chitosan. The treated fibers exhibit lower whiteness index
crosslinking agent is required. It should samples are rinsed again with distilled (WI) with the increase in chitosan
be nontoxic and nonirritating during the water and dried at room temperature concentration from 1 to 5 g/L. The
use and storage; nevertheless, under vacuum until to reach a stable degree of WI is found six times lower
formaldehyde is one of the mostly used mass. than that the concentration of 5 g/L
compounds and presents the limitation [66]. Modified chitosan is also used for
in those aspects due to its The mechanism involved in the the hydrophobic drug delivery [67].
spontaneous toxic vaporization [64]. process follows two steps. In the first
step, the crosslinking reaction between Chitosan: a flame and fire retardant
There are some other crosslinkers such cellulose and polycarboxylic acid/CA material for textile
as glutaricdialdehyde, butane takes place by the formation of
tetracarboxylic acid, citric acid (CA), carboxylic anhydride. In the second Flame retardant textiles are highly
potassium permanganate, and sodium step, the rings open to react with the recommended, especially where the
hypophosphite that form the covalent polysaccharide through the alcohol working environment is highly
bond between chitosan and the groups and form the ester bond. The concerned regarding fire or flame. The
cellulose fabrics by an ester bond. use of maximum 2.3 w/w% NaH2PO4 flame retardant property is considered
accelerates the fixation through when the flame is not permitted to
A high intensity of UV lamp at a esterification due to the presence of propagate and extinguished at the same
wavelength of 254 nm is applied to the the phosphate and the partial sodium time of withdrawing the fire source.
raw fibers and exposed for 4 h before salt of the polycarboxylic acid. The Phosphorus-based materials are
the crosslinking treatment. The content increased amount of NaH2PO4 affects interesting and well known as flame
of chitosan is 40% less in the final the chitosan loading with fibers due to retardant due to low toxicity and
treated fiber compared to the raw fibers the neutralization of free carboxylic absence of halogen compounds. These
without UV irradiation before the groups and inhibits esterification of the materials are quite efficient as a flame
treatment with chitosan. It usually hydroxyl moieties present in chitosan. retardant for cellulose and its
changes the surface polarity of fibers The unreacted amino moieties act as derivatives through dehydration and
via photooxidation and forms active active antibacterial property. char production. In phosphorylation
carboxylic groups by photodestruction process, cellulose is treated with
of glycosidic bonds and rings. The Sustainability requires a process safer diammonium phosphate in the
fixation of chitosan with UVirradiated in terms of raw materials and finished presence of urea.
cellulose fiber is more stable than the products excluding any toxic by-
raw fibers according to the product. In this aspect, reference [64] Chitosan could be paired with
thermogravimetric analysis. In this proposes UV radiation for generation phosphorous derivative to build an
process, a fixed amount of chitosan of reactive sites on chitosan that can intumescent flame retardant
and NaH2PO4 is mixed in distilled fix many compounds through compound. Chitosan is a nitrogen-
water. Then, citric acid (CA) is added crosslinking without using any toxic containing polysaccharide, biodegrada-
to the aqueous solution as an acidifier chemical compounds. ble, biocompatible, and environmenta-
and crosslinking agent. lly nontoxic. It provides a char-forming
Moreover, the antibacterial colloid is property when it is used as
The process could be carried out prepared by blending chitosan and intumescent additives due to its
excluding NaH2PO4 based on the AgCl–TiO2 at a ratio of 1:5. A cotton hydroxyl and amino groups on

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