‘GREEN’ FINISHING FOR CELLULOSE AND PROTEIN-BASED FIBERS AND FABRICS
Most apparel and textile products undergo various finishing treatments to attain aesthetic and functional properties. In many cases toxic chemicals are used in these finishing treatments. For example, formaldehyde-based chemical agents have been commonly used to treat cotton fabrics to attain ‘easy-care’ properties. Similarly, fluorine-based chemicals are used to attain self-cleaning or superhydrophobic fabrics. Formaldehyde and glutaraldehyde are used to crosslink keratin-based fibers such as wool and hair to improve their mechanical properties or to attain durable hair styling effects. Environmental issues and consumer awareness about synthetics have promoted the use of natural fibers to manufacture products that have improved environmental profiles. Consumer awareness and concerns about the use of formaldehyde, perfluoroalkyl substances (PFAS), glutaraldehyde and glyoxal, commonly used finishing agents for natural fabrics such as cotton and wool have prompted manufacturers to find greener and sustainable solutions. These chemicals are not only toxic but are known to bioaccumulate in nature for long time and can find their way into human body through direct skin contact and water. This research highlights the current textile chemistry that goes into finishing the fabrics. It also states some of the greener alternatives developed so far. The main aims of this research, however, are to develop sustainable and ‘green’ chemistry-based solutions for creating wrinkle-free cotton fabrics, superhydrophobic cotton fabrics and for crosslinking of wool fibers to increase their strength as well as for stabilizing and shaping of human hair. The research was also focused on developing such finishing processes using inexpensive, readily available and renewable (mostly plant based) raw materials and in many cases, wastes or by-products generated in food processing. Sucrose and cyclodextrin-based multifunctional carboxylic acid were synthesized as ‘green’ crosslinkers for crosslinking cellulose, separately, to create wrinkle-free cotton fabrics. A green process of covalently bonding multi-shaped silica particles synthesized from tetra ethyl ortho silicate (TEOS) and fatty acid grafting was developed to create superhydrophobic cotton fabrics. Sucrose and soy flour sugar based crosslinkers were developed to enhance the strength of the wool fibers to enhance its ability to be spun into finer yarns as well as to reduce breakage during spinning and weaving and, thus, reducing the defects in both yarns and fabrics. The effects and durability of these chemical treatments on the fabrics were characterized. Sugar-based crosslinker was developed to treat human hair for creating internal crosslinks for hair-styling and stability that was durable to high humidity environment as well as shampoo washings.