In recent years, new concepts in textile dyeing technology have been investigated which aim to decrease the use of chemicals and the emission of water. In this work, dyeing of cotton textiles with reactive dyes has been investigated in a silicone non-aqueous dyeing system. Compared with conventional aqueous dyeing, almost 100% of reactive dyes can be adsorbed on cotton textiles without using any salts in non-aqueous dyeing systems, and the fixation of dye is also higher (80%~90% for non-aqueous dyeing vs. 40%~50% for traditional dyeing). The pseudo-second-order kinetic model can best describe the adsorption and equilibrium of reactive dyes in the non-aqueous dyeing systems as well as in the traditional water dyeing system. In the non-aqueous dyeing systems, the adsorption equilibrium of reactive dyes can be reached quickly. Particularly in the siloxane non-aqueous dyeing system, the adsorption equilibrium time of reactive dye is only 5–10 min at 25 °C, whereas more time is needed at 60 °C in the water dyeing system. The surface tension of non-aqueous media influences the adsorption rate of dye. The lower the surface tension, the faster the adsorption rate of reactive dye, and the higher the final uptake of dye. As a result, non-aqueous dyeing technology provides an innovative approach to increase dye uptake under a low dyeing temperature, in addition to making large water savings.

Disperse dyeing for polyethylene terephthalate (PET) fiber in different non-aqueous solvent dyeing systems have been extensively studied over the past decades. In the present work, disperse dyeing for PET was investigated in a silicone solvent dyeing system. The influence of accelerant on the fiber swelling, uptake of dye, K/S value of dyed fiber, and dye solubility in the silicone solvent were systematically investigated. Compared with no accelerant, the final uptake of the disperse dye (C. I. Disperse Blue 367) could increase to 81% with 20% accelerant in the silicone solvent dyeing system, and the K/S value of dyed fiber was also higher (3.3 for no accelerant vs. 13.2 for accelerant). The influence of accelerant on the performance of disperse dyeing was also studied. Firstly, the solubility of the disperse dye in the silicone solvent can be decreased by the accelerant. Moreover, the solubility of the disperse dye is inversely proportional to the K/S value and the uptake of the dye. In addition, although the silicone solvent can diffuse to the inner fiber and has a partial swelling in the PET fiber, the swelling of PET can be improved by the accelerant. Furthermore, the swelling of fiber can reach equilibrium when the amount of accelerant was 15% (the weight of fiber). Therefore, this eco-friendly dyeing technology has considerable potential for application to a broad array of chemical fibers.

Reactive dyes maintain a long reaction with fiber and show a high dye uptake and fixation rate, and effectively decrease the dyeing waste water in siloxane reverse micro-emulsion. However, little research has been carried out into the hydrolysis reaction of reactive dyes in reverse micro-emulsion. In this study, Reactive Blue 19 was selected as a model vinyl sulfone reactive dye to study its hydrolysis in siloxane reverse micro-emulsion. The hydrolysis reaction was analyzed using high performance liquid chromatography. The results show that the hydrolysis rate of vinyl sulfone dyes in siloxane reverse micro-emulsion was slower than that in a traditional bath. Influences due to the ratio of aqueous dye solution to siloxane, non-ionic surfactant, cellulose fiber, and temperature on the hydrolysis reaction of vinyl sulfone reactive dye were also researched. The results show that with more aqueous solution emulsified in the siloxane media, the hydrolysis reaction of vinyl sulfone dye is faster. Reactive dyes were emulsified into a water micro-environment with non-ionic surfactant, which formed reverse micro-emulsion, and decreased the content of free water; this further influenced the hydrolysis of reactive dye.

The smart cleaning ability of cotton fabrics is realized by cross-linking thermo-responsive random copolymer to the cotton. Poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-ethylene glycol methacrylate), denoted as P(MEO₂MA-co-EGMA), is synthesized from 2-(2-methoxyethoxy)ethoxyethyl methacrylate (MEO₂MA) and ethylene glycol methacrylate (EGMA) with a molar ratio of 17 : 3. Its dilute aqueous solution (1 mg mL⁻¹) presents a lower critical solution temperature (LCST) of 38 °C. Furthering increase the solution concentration, the LCST shifts towards lower temperature. By applying citric acid as a cross-linker, P(MEO₂MA-co-EGMA) is successfully immobilized onto cotton fabrics. The obtained cotton fabrics also possess thermo-responsive property with a LCST at 37 °C. The smart cleaning ability is confirmed by single fiber cleaning experiments using a confocal microscope. It is observed that the cleaning ability of the cotton with cross-linked P(MEO₂MA-co-EGMA) can be prominently enhanced at low temperature (below LCST). In addition, due to the low glass transition temperature of P(MEO₂MA-co-EGMA) (−26 °C), the polymer is in a gel state at room temperature and will not negatively impact fabric softness. P(MEO₂MA-co-EGMA) is a promising candidate for preparing textiles with smart cleaning ability and great fabric hand.

The main goal of this article is to study the diffusion mechanism of aqueous solutions and the swelling of cellulosic fibers in the silicone non-aqueous dyeing system via fluorescent labeling. Due to non-polar media only adsorbing on the surface of fiber, cellulosic fiber could not swell as a result of the non-polar media. However, because water molecules can diffuse into the non-crystalline region of the fiber, cellulosic fiber could swell by water which was dispersed or emulsified in a non-aqueous dyeing system. To study the diffusion mechanism of an aqueous solution in the siloxane non-aqueous dyeing system, siloxane non-aqueous media was first diffused to the cellulosic fiber because of its lower surface tension. The resulting aqueous solution took more time to diffuse the surface of the cellulosic fiber, because water molecules must penetrate the siloxane non-aqueous media film. Compared with the fluorescent intensity of the fiber surface, the siloxane film could be re-transferred to the dye bath under the emulsification of the surfactant and the mechanical force. Therefore, a longer diffusion time of the aqueous solution ensured the dyeing feasibility for cellulosic fiber in the non-aqueous dyeing system.