| In the main textile fibers, viscose fiber has the best moisture content which meets the physiological requirements of human skin, it also has another properties such as smooth, cool, breathable, anti-static, stain gorgeous and so on. Reactive dyes are widely used in viscose fiber dyeing. However, it is need to add large amounts of inorganic salts to promote dyeing when dyeing with reactive dyes, which will produce a lot of dyeing waste water containing inorganic salts, so it is not comply with the requirements of the current development about low-carbon and environment friendly. Therefore, this paper synthesized a cationic modifier EPI-DMA-THPS for cationic modification of viscose fiber, in order to achieve dyeing with low-alkali and salt-free. The paper mainly includes the following contents:(1)Using epichlorohydrin(EPI) and dimethylamine(DMA) as the raw materials, ethylenediamine as crosslinking agent, prepared polyquaternium EPI-DMA by stepwise polymerization process; then THPS was grafted onto EPI-DMA through etherification reaction to get EPI-DMA-THPS. The structure of the product was characterized and the synthesis conditions were systematically studied. The optimal synthesis conditions were as follow: the molar ratio of EPI and DMA was 1.5: 1, the amount of ethylenediamine was 3%, the reaction temperature was 70℃, the reaction time was 5h; the volume ratio of EPI-DMA and THPS was 20: 2, the etherification temperature was 65℃, the etherification time was 5h.(2)Modified viscose fiber with cationic modifier EPI-DMA-THPS, and studied the effect of modification conditions on viscose fiber’s dyeing effect with salt-free, then characterized and tested the modified fiber. The results showed that, EPI-DMA-THPS had good stability in the alkaline environment, the concentration of sodium hydroxide had little impact on modification effect, the viscose fiber which was modified with concentration of sodium hydroxide ranges from 2g/L to 10g/L had good dyeing effect, the exhaustion maintained at above 97.0% and fixation maintained at above 90%, when dyeing with salt-free; the modified viscose fiber had excellent antibacterial activity, whose antibacterial rate against Staphylococcus aureus was 95.5%; the crystallinity, thermal stability and mechanical properties of modified viscose were not changed. The optimum modification conditions were as follows: the viscose was modified through pre-adsorption under room temperature, then slowly elevating temperature to 85℃, the pre-adsorption time was 5min, the heating rate was 1℃/min, the modification time was 60 min, the concentration of Na OH was 2-10g/L.(3)Studied the salt-free dyeing of modified viscose fiber, systematically studied the effect of dyeing conditions on exhaustionã€fixationã€K/B, and compared the product’ performance with traditional dyeing product. The optimum dyeing conditions were as follows : the concentration of Na2CO3 was 1g/L, the dyeing temperature was 60℃, the dyeing time was 50 min. When dyeing with 3%o.w.f turquoise blue dye under these conditions, the exhaustion and fixation could reach 98.0% and 93.6% respectively; compared with the traditional dyeing, the salt-free dyeing of modified viscose fiber improved the fixation and K/B significantly, and the dry/wet rubbing fastness, light fastness of dyed fiber met the requirements to wearing.(4)The medium-scale experiment included synthesis of modifiers, modification of viscose fiber and dyeing with salt-free. Compared with the small samples experiment in the laboratory, the exhaustion of medium-scale experiment was decreased slightly from 98% to 97%; However, compared with the traditional dyeing, whose exhaustion was 58.2%, it still had improved significantly. |
