Study On The Improvement Of Light Fastness Of Pyrrole-structured Biomass Pigments

Biomass pigments are synthesized by organisms,which can be extracted from plant or animal bodies,or can be obtained by microbial fermentation.Compared with synthetic dyes,it has the advantages of sustainable source,biodegradability,low risk,and can give fabric functionality.However,the dyeing performance of biomass pigments is poor,such as lower dyeing rate and color fastness,especially the problem of color fastness to sunlight is more serious.This subject investigates the problem of light-fastness of biomass pigments.Taking brightly colored microorganisms to produce red pigment prodigiosins as a research object,investigate the influencing factors of its light stability,explore the method of improving the fastness of dyed fabrics,and explore the mechanism of dyed fabrics'fading to promote the application of biomass pigments in the textile field.Taking the degree of photofading of prodigiosins dyed fabric as an evaluation index,the influencing factors of light-fastness of prodigiosins dyed fabric were analyzed in terms of the influence of fiber types,the combination of pigment and fiber,and environmental factors.Studies have shown that,in external conditions,light is the direct factor that causes dyed fabrics to fade;the higher the proportion of crystalline regions of dyed fibers,the greater the degree of aggregation of dyes on the fibers,which will slow down the rate of dye photochemical reactions and improve the light-fastness;the stronger the binding force of dyes and fibers,the higher the fastness of dyed fabrics;through metal ion mordant,they become complexes with the dye molecules,increasing the molecular weight of the dye,which can significantly improve the fastness of sunlight,The best effect is Al³⁺post-mordant dyeing.The effects of light wave,light intensity,light time,and dye concentration on the photostability of pigments were analyzed,and the light-irradiated products of prodigiosins were analyzed by FTIR,HPLC and UV-Vis spectra.The mechanism of prodigiosins was found.After light irradiation treatment,the characteristic peak of prodigiosins in the spectrum,and no new peak appeared.It is speculated that what happened to prodigiosins was a photolysis reaction.Based on the analysis of the influencing factors and light fading mechanism of prodigiosins,a method was designed to improve the fastness to sunlight by treating dyed fabrics with biomass mordant and light stabilizer.The mordant was screened and a mordant process was developed.The results showed that tannic acid and mordant dyeing had excellent effects on improving the fastness to sunlight.The best process for tannic acid mordant dyeing was 8 g/L tannic acid concentration,p H 2.1,dyeing temperature 90?,and dyeing time 40 min.Based on the best mordant process,the use of biomass antioxidants and UV absorbers to post-finish the mordant fabrics,it was found that the synergistic effect of tannic acid and flavones has a significant effect on improving the fastness of sunlight.The rubbing and soaping fastnesses meet the requirements for textiles,and the sun fastness has been improved by 1 level.