Chitosan Coating on Textile Fibers for Functional Properties

Chitosan is a biopolymer with unequalled properties such as biodegradability, nontoxicity, and antimicrobial activity. It is a carbohydrate polymer derived from the deacetylation of the chitin component of the shells of crustacean; hence, it is a renewable material widely available as a byproduct of the food industry. Owing to its extremely interesting properties, chitosan has been extensively applied to textile fibers to confer various functional properties such as • antimicrobial activity with a green chemistry approach for aesthetic, hygienic, and medical applications; • antifelting properties for wool fabrics; • increasing uptake of ionic dyes in dyeing processes; • removal of dyes and other organic pollutants from wastewaters; • removal of heavy metal ions from contaminated wastewaters. A fundamental problem that arises in order to obtain durable chitosan coatings on textiles is due to the low wash fastness of the biopolymer; hence, thermal treatments or cross-linking agents are needed to obtain strong bonding with the fibers. Wet thermal curing involves energy consumption and possible fiber degradation, whereas the most of cross-linking agents such as dialdehydes are toxic. Therefore, many research works were aimed to investigate safer grafting methods with physical means such as UV irradiation or with green chemicals.