Relationship Between The Structure Of Natural Dyes And Its UV-protective Properties

Natural production is decomposable and friendly to the environment. The fabric dyedwith natural production not only have good UV-protection, but also have suppleness, goodhygroscopicity, comfort etc，so the fabric dyed with natural production must has a greatimprovement on the idea pursuing naturalness of customers. Several kinds of natural dyeswere selected in this study as a UV-protective absorber on silk. The relationship betweenthe structure of natural dyes and its UV-protective properties were discussed.Pre-cheated the silk fabric with natural dyes, and then finished in3different ways toenhance its color fastness in the UV-protective finishing process. Whether different kindsof fixation, concentration, pH of finishing solution, temperature, time could make adifference on the UV-protective properties of silk.After finished by the optimal process,some tests such as breaking strength、gas permeability were carried out on the silk fabrics,what’s more, the structure and thermal stability of treated fabric were determined throughTG test and XRD.Experimental results revealed that the fabrics dyed with lac and turmeric had goodultraviolet protective properties. After finished by the optimal process, the UPF of the silkwas3-4times then before. The results also showed that different colors were got withdifferent chelation. The fabric got color and UV-protective properties at the same time. Thefabric treated with lac dye had good solarization fastness, and the silk got a higher UPFvalue after solarizing. The breaking strength and gas permeability of the finished silk werehardly changed. Thermal stability developed through TG. From the figures of XRD oftreated and untreated fibers, it was shown that crystal structures of finished fabrics werehardly changed. The results revealed that the silk finished by natural dyes has a great valueof exploration and application.