Many natural polymers have special structure and biological activity, and most of them are non-toxic and can be naturally degraded. It will be the development trend of green fabric finishing additives in the future to modify them to become new fabric finishing additives.

The kinds of natural functional finishing agents can be divided into animal and plant: in animal, the post-processing of chitin and deacetylated chitosan is attracting people's attention. In addition, collagen, silk fibroin powder, hyaluronic acid and squalene are being used to soften fiber clothing, keep skin warm and keep moisture; plant functional agents include Artemisia argyi, aloe vera, Houttuynia cordata, licorice, etc.

Most of these natural polymers are polysaccharide compounds formed by the combination of β - 1,4-glucoside, and their main chain generally contains a large number of active groups such as hydroxyl, ketal, carboxyl, amino and so on. These active groups can not only carry out etherification, carboxymethylation, alkylation, acylation, sulfonation and other reactions, but also cross-linking reaction with the active groups on the surface of the fabric, and can produce strong hydrogen bonding, so as to form a polymer film on the surface of the fabric which can give the fabric certain functionality.

(1) Chitosan: chitosan is very soluble in water, the amount of chitosan used in fabric treatment is very small, and the dip rolling solution can be used repeatedly, the process is simple and easy, just need to roll and dry. When used for fabric finishing, it can not only keep the water absorption and air permeability of cotton fabric, but also has the functions of shrink proof and straightness. It can be used for antibacterial, deodorizing and moisturizing finishing of fabrics. In China, it can also be used as film-forming agent for pigment printing, antibacterial and mildew resistant products of chitosan, etc. Chitosan fiber can also be used to make clothing with far infrared thermal sensitivity.

(2) Squalene: squalene is a kind of lipid, which can be extracted from the liver of shark turtle. It contains substances with high affinity with human skin, and can be used as a natural functional finishing agent for fabrics. The finished fabric is safe and comfortable, and has good wettability, softness and moisture retention.

(3) Sericin: the sericin recovered and refined from natural silk scouring solution can be used for soft and comfortable finishing of fabrics. Sericin contains a lot of amino acids. The content of serine is the highest, accounting for about 1 / 3, aspartic acid and glutamic acid are more than 10%, which has good moisture retention. The finished fabric is soft and comfortable, and can make the skin smooth when wearing.