The antimicrobial properties of natural dyes are due to the presence of various compounds such as anthraquinones, flavonoids, tannins, naphthoquinones, etc. Although natural dyes improve the UV protection properties of textiles, there are some limitations associated with this.
Di-hydropyrans
Quercetin, a flavonoid, was reported to provide better antioxidant, antibacterial and UV protection to silk fabric [81]. Flavonoids and anthocyanin from the peel of red onion (Allium cepaL.) are natural dyes with antibacterial activity and UV protection after application to wool and cotton fabrics [82].
Anthocyanidins
Carotenoids
Tannins
Conclusion
Comparison of UV protection properties of woolen fabrics dyed with yellow natural dyes from different plant sources. Dyeing and deodorizing properties of cotton, silk and wool fabrics dyed with various natural dyes.
Introduction
These chapters discuss the characteristics of dyeing chemicals and how auxiliaries can help achieve outstanding dyeing performance. However, in recent years there has been significant evidence of a lack of knowledge about the use of paint chemicals.
Dyeing chemicals
- Chelating agent
- Dispersing agent
- Leveling agents
- Electrolyte
- pH control agents
- Surfactants
- Anti-foaming agents
- Reducing agents
- Softeners
The mechanism of disperse dyeing is categorized into four stages: (i) dissolution of dye in water by the formation of dye micelles with dispersing agents; ii) transfer of dye molecules from the solution to the fiber surface; iii) refilling the dye bath by dissolving the solid material from the dispersion; and (iv) dye diffusion into the fiber (Figure 6). To ensure stability, the amount of dispersing agents must be maintained in the dye bath [8]. Werner [4] investigated that the formation of dyes and leveling agents represents similar connections to that occurring in fiber dyeing.
The dyeing process can lead to the formation of macro and microfoam during circulation of dyes and auxiliaries in the dye bath. A macrofoam is displayed with large bubbles that are visible on the surface of the system and produce cosmetic imperfections [41]. A decrease in foam occurs with an increase in the hydrophilicity of the co-polymers.
At the beginning of the nineteenth century, sodium dithionate (Na2S2O4) was introduced as a reducing agent for vat dyeing [8].
Conclusion
Azo dyes are a class of compounds containing an N=N double bond and, due to their ability to absorb visible to near-infrared (NIR) light and ease of synthesis, have been used in the textile, fiber, leather, dyeing and printing industries for over a century. Near-infrared absorbing dyes have attracted considerable interest for their uses in the development of functional materials for high-tech end uses. Considerable interest has been shown in recent years in the design of near-infrared absorbing organic azo dyes.
They find many applications in high-tech fields such as dye-sensitized solar cells (DSSCs) [15], laser optical storage systems [16], transparent coatings [17], organic. There are no further reports of the use of 2-hydroxy-1,4-naphthoquinone in the synthesis of azo dyes. The reactions of 2-hydroxy-1,4-naphthoquinone in the synthesis of azo dyes for NIR-absorbing dyes were investigated in our previous work.
The aim of this work is to synthesize new molecules containing phenazine and azo cores, which were predicted in a single molecule with the aim of improving photophysical properties in the NIR range.
Result and discussion 1 Synthesis strategy
Optical properties
The dyes (12–14) showed absorption at 620–710 nm due to the intramolecular charge transfer transition (ICT) between the donor-acceptor pair (Figure 7 and Table 1).
Experimental sections
General experimental procedure of the azo dyes (18–20)
General experimental procedure of the azo-phenazine dyes (12–14)
General experimental procedure of 2,3-diaminophenazine (21)
Characterization
Conclusions
Synthesis and Optical Properties of Near Infrared (NIR) Absorbing Azo Dyes DOI: http://dx.doi.org/10.5772/intechopen.81229. NIR absorbing dyes are developed and new structural designs of the dye chromophore molecules are studied. Azo dyes are the most important class of organic dyes, but many of azo dyes are suspected to be carcinogenic in nature.
Therefore, color research is aimed at developing new type of chromophores.
Future trends
Near-infrared absorbing azo dyes: synthesis and X-ray crystallographic and spectral characterization of monoazopyrroles, bisazopyrroles and a boron-azopyrrole complex. The synthesis, characterization, thermal and optical properties of copper, nickel and vanadyl complexes derived from azo dyes. The amount of the dye adsorbed onto the polymeric resin is studied over time to estimate the adsorption mechanism.
The results of the studied kinetic model clarify that the experimental results for adsorption of MB on R1, R2 and R3 can be described by a kinetic model supporting chemical adsorption. High potential health risk is caused by adsorption of azo dyes and their degradation products (toxic amines) by the gastrointestinal tract, body, lungs and formation of hemoglobin adducts, as well as disturbance of blood formation [3]. In particular, the azo dyes that are most advertised and cause cancer should be taken seriously.
Most dyes used in the textile industry are fade resistant and non-biodegradable.
Materials and methods 1 Synthesis of composite resins
Sorption studies
Sorption experiments were performed on methylene blue dye solutions with prepared sorbents in batch and column techniques. Batch experiments were performed with 100 ml of 110 5M methylene blue solution in 250 ml stoppered bottles containing 0.1 g of composite material at pH 5.5. The parameters affecting the sorption process were studied by changing one of the parameters and keeping the other parameters constant.
The solid material was separated from the solution using a centrifuge and the concentration of dyes in the solution was determined. All experiments were carried out in the Chemistry and Technology of Natural and Synthetic Dyes and Pigments room. Desorption of solutes from the packed column was carried out by elution with (H2SO4+ H2O2), HCL, NaOH, CH3COOH, C2O4H2 and C6H8O7.
From the beginning of the experiment, effluent samples of different volumes were collected at the bottom of the column for analysis.
Results and discussions
Characterization of the sorbent materials
On the other hand, Figure 2(a–c) XRD analysis of HAP samples indicates that the samples are in the crystalline phase. In addition, the XRD pattern shows a broad reflection peak in the range of 31.7–32.8 of 2 values, which corresponds to the characteristic peak of hydroxyapatite. The thermogravimetric analysis (TGA) measurements were performed in flowing nitrogen gas on the prepared resins R1, as shown in Figure 4. a) Infrared spectrum of the HAP samples and (b) Infrared spectrum of the synthesized R1 and R1/MB.
It is clear that the presence of HAP with the polymer increases the thermal stability and slows down the thermal degradation of the polymer. a) X-ray diffraction of as-synthesized HAP, (b) X-ray diffraction of as-synthesized R1, and (c) X-ray diffraction of R1 after MB sorption. Thermal decomposition of apatite content depends on hydroxide and phosphate content; both are related to the change in apatite mass upon heating. Calcium phosphates containing HPO4 lose weight between 400 and 700 °C due to the formation of pyrophosphate and evolution of water.
After 700 °C, calcium pyrophosphate is reported to react with HAP to produce TCP and water.
Sorption investigations of methylene blue dye .1 Batch investigations
This may refer to the aggregation of sorbent particles at high MB dye concentration. Effect of particle size on the adsorption of MB from aqueous solutions to apatite resins. Effect of resin dosage on MB adsorption from aqueous solutions to apatite resins.
Kinetic plot of the pseudo-first-order model for the sorption of MB on the synthesized sorbents R1. Kinetic plot of the pseudo second-order model for the sorption of MB on the synthesized sorbents R1. The adsorption of MB on R1 was studied at different initial dye concentrations (within the range of 1–50 mg/L).
The results show that MB dye removal slightly increases with increasing temperature, see Figure 15.
Influence of sewing thread on seam quality
Therefore it is very important to choose the right coating for better performance of the coating. Seam types are one of the factors that affect the overall performance of a seam in terms of durability, comfort and potential for change. The appearance of a seam is generally governed by the proper relationship between thread size and type, stitch density and types, and fabric texture and weight [11].
Many researchers have found that fabric quality parameters such as fabric density, fabric thickness, tensile strength, elongation, bending stiffness, and shear stiffness have a great influence on seam quality [12]. Experts revealed that a seam is judged on its analytical dimensions such as strength, creasing property, efficiency, slip strength and seam strength. In this stage, damage to the sewing thread and the warp and weft in the fabric results in poor seam performance by reducing seam strength and seam slippage [14, 15].
One of the performance characteristics of the seam is the abrasion resistance of the seams, which is determined by the seam threads.
Influence of fabric parameters on seam quality
Plain cotton fabrics show higher seam elongation in the warp direction, whereas twill weave cotton fabrics show higher seam elongation in the weft direction. This is attributed to the fact that during sewing, the suture threads may be subjected to stretching and bending, resulting in shrinkage in the relaxation process after sewing operation [26]. On the other hand, hand cotton dominant fabric shows a high drape coefficient as cotton has more bending stiffness than polyester [28].
Seam strength
Seam strength efficiency
This is due to the fact that polyester gives higher flexibility in the low load region, thus reducing the dimensional stability of the fabric. The decrease in seam efficiency is due to the less uniform fiber matrix causing yarn slippage and yarn failure. Higher linear density sewing thread has better grip with textured polyester in polyester-dominant fabric, resulting in high seam strength efficiency.
However, the seam strength performance is increased with a cotton-dominant fabric due to the uniform fiber matrix [1, 29]. This is attributed to the fact that a certain flexibility of the seam occurs at low thread tension under a sudden load. In contrast to high tension, the fabric was pulled along the seam line, resulting in a wrinkled and unstable seam [17].
Seam efficiency increases with increasing linear density of sewing thread due to the greater number of fibers included in the coarser sewing thread [14, 19].
Seam puckering
Seam slippage
Seam damage
Conclusion
Prediction of seam performance of commercial woven fabrics using multiple logarithm regression and artificial neural networks.
