Whiteness Index on Cotton Fabrics Due to Chitosan Curing Temperature

Chitosan is an N-deacetylated biopolymer derivative of chitin (2-acetamido-2-deoxyβ-D-glucose through a β (1-4) linkage). The deacetylation is never complete. There is no specified nomenclature that describes the degree of deacetylation [1]. Chitin can be easily acquired from crab or shrimp shells. Its N-deacetylation is performed under alkali environment. The chitin that has been obtained from the shells is deacetylated in 40% sodium hydroxide at 120 °C for 1-3h. This produces 70% deacetylated chitosan. Most natural polysaccharides are neutral or acidic, but chitin and chitosan are highly basic polysaccharides [2]. The bonding between chitosan and cotton is a difficult bond because of the likeness of the two polymers. To improve the bond the chitosan is dissolved in an acid. After that, chitosan is able to react with oxidised cotton fabric, for this reason it has a wide range of applications. It is most known for its use in wound dressing [3-5]. However, it can be used in a lot of other areas, such as cosmetics, as artificial skin, as contact lens, for heavy metal capturing in polluted water, colour removal in textile mills, paper finishing, drug delivery system, etc. But its most important feature might be the fact that is an antibacterial agent [2, 6-7]. It should be pointed out that to carry out the covalent bond formation between the -OH groups of cellulose and the NH2 groups of chitosan, it is necessary to apply high temperature of curing after the treatment giving a better fixation in this case [8]. In order to study the influence of the concentration of chitosan used to treat the cotton fabric and the optimum temperature in the curing, the whiteness test was performed to see a change of colour in the cotton.