Study On Microbial Dyeing Of Silk And Silk Fabrics

In this paper, in order to explore a new ecological dyeing method, tussah silk and silk fabrics were dyed using biological methods. Ecological dyeing using Monascus and Janthinobacterium lividum were discussed respectively. During the dyeing process, tussah silk and silk fabrics were dipped directly in the low temperature dye bath without extraction of pigment. Skipping the traditional bottlenecks, natural colored silk fabric dyeing with nonchemical dyes meets the consumption concept of return to natural and environmental protection requirements. And its low carbon characteristic meets the national development strategy of sustainable development, and would promote the printing and dyeing industry of green ecological significantly.During the ecological dyeing using Monascus, the bacterial morphology and cultural characteristics of Monascus were investigated firstly. Then the r DNA D1/ D2 and ITS gene sequences of this strain were identified using primers of a Fungi Identification PCR Kit(Code No.RR178) from Ta Ka Ra company. The results showed that the strain shared more than 99% homology with the Monascus reference strain. The silk fabrics dyed under optimal process were tested. The results showed that soaping fastness fade level 4, staining level 4-5, the dry and wet rubbing fastness grade 4, light fastness grade 3. The XPS results showed Monascus dyed silk fabric not only contain C, O and N elements, but also appeared in S, P elements, N content increased significantly.Secondly, Monascus ecological dyeing method was optimized by screening bacterial culture time, comparing method of dye preparation and screening dyeing temperature and time. The effects of different mordants, different amount of mordant and p H of dye bath on dye-uptake were discussed. The optimal dyeing process was as follows: Monascus inoculated to the seed culture medium, 180rpm/min, culture 7d, fermentation 30°C, color value reached 21.3U/ml, put fermentation culture solution into the shredder to maintain 5min at 8000 rpm for mashing the mycelia, static 12 h, filtration by 6 layers gauze, rare earth mixture as a mordant was added in the filtrate(which contains 25.52 wt.% La2O3 and 50.82 wt.% Ce O2), the concentration of mixed rare earth was 0.2-0.4g/L, get the dyeing solution after mixed evenly, the p H of dyeing solution was adjusted to 3.6 by citric acid, tussah silk and silk textile was placed directly in the dyeing solution in 1:20 dye bath ratio, then continue dyeing at 30°C at 180 rpm for 3 hours, removed the dye tussah silk and silk textile, washed with pure water for 5~10 minutes, dried at 95 ~ 98 °C.Lastly, the structure and properties of tussah silk fibers under optimal process were investigated and compared with ordinary tussah silk by X-ray diffraction, sonic modulus method, thermal performance analysis and mechanical properties tests. The results showed that the crystallinity and orientation degree of the colored tussah silk was a litter higher than ordinary tussah silk. The strength of colored tussah silk was 6.5% higher than ordinary tussah silk, but the elongation decreased by 3.5%, the initial modulud increased by 3.6%. The softness of ordinary tussah silk was more excellent.During the ecological dyeing using Janthinobacterium lividum, the bacterial morphology and cultural characteristics were investigated firstly, based on which the bacterial growth curve and pigment concentration standard curve were drawn. Secondly, Janthinobacterium lividum ecological dyeing method was optimized. The effect of dyeing temperature and time on apparent color depth and the effect of dyeing time on dye-uptake were evaluated. The optimum dyeing process was as follows: use a small amount of strain slant culture medium inoculated to the seed culture medium, 200rpm/min, culture 3.5d, fermentation 20°C, bacteria concentration of seed liquid was adjusted to1-2×108 cfu/m L. Then inoculated to the fermentation culture medium according to 6%, 200rpm/min, culture 7d, fermentation 20°C, The sterile electricity texture silk fabrics were added in fermentation culture solution directly in 1:20 dye bath ratio. Dyeing at 70°C at for 3 hours, removed the dye tussah silk and silk textile, washed with pure water for 5~10 minutes, dried at 95 ~ 98 °C. Lastly, the silk fabrics dyeing under optimal process were tested. The results showed that K/S value was 6.0875, dye-uptake was up to 89.22%, soaping fastness fade level 4, staining fastness level 4-5,the dry and wet rubbing fastness grade 5, light fastness grade 1. The XPS results showed Janthinobacterium lividum dyed silk fabric not only contain C, O and N elements, but also appeared in S, P elements, N content increased significantly.