**4.2. Dyeing silk fabric with UMP**

Silk is a natural protein fiber, and the shimmering appearance of silk is due to the triangular prism-like structure of the silk fiber, which allows silk cloth to refract incoming light at dif‐ ferent. But the silk fiber also has some defects, such as the problem of bleaching, the loss of pupa protein and the yellowing [50,51].

In order to improve the performance of the silk fiber, silk was modified with cationic disper‐ sant [52]. This improved substantivity of UMP due to the introduction of cationic groups in‐ to the silk fabric, and the balance might be due to the adsorption of cationic reagent on surface of silk fabric reaching saturation values. In this situation, more cationic reagent mol‐ ecules combined with UMP. The bounds between UMP and silk fabric led to a higher K/S values. The different amount of the cationic reagent in pretreatment could impart different amount of positive charge to silk surface, which could affect the K/S values. The UMP was not substantive to silk, the K/S values were low on silk without cationization pretreatment. The K/S values greatly increased and then kept in a balance with the increase of the cationi‐ zation concentration [53].

Furthermore, penetration property and content of ammonium of silk would also restrict to produce the stronger ionic attraction between the cationic fiber and the anionic UMP. As a result, the adsorption of UMP on silk fabric did not change any more accordingly [54]. Wei reported that after modifying with glycidyltrimethylammonium chloride (EPTAC), the reac‐ tions of some amino acids were more rapid than the reaction of glucose. The dyeing ability of modified silk fiber had been improved remarkably. A theory which was called "fixed points" was given to this phenomenon [51]. Wang found that pH in pretreatment affected significantly on the dyeing properties of silk fabric with UMP, because in alkali condition, the chlorohydroxypropyl group of 3-chloro-2-hydroxypropyltrimrthylammonium chloride (CHTAC) converted to an epoxy group and then formed 2, 3-epoxypropyltrimethylammoni‐ um chloride which reacted with the nucleophilic amine group in the silk. And The highest K/S values could achieve at pH 8 [53].

With the increase of cationic reagent concentration, the rubbing fastness values appeared in‐ creasing trend (Table 1). The washing stain fastness of treated fabric was similarly compara‐ ble to the results without fastness improving reagent treatment because the UMP had no affinity with silk without treatment. Compared with untreated silk, the washing change fast‐


nesses of cationic silk increased greatly. This was probably due to the fastness improving re‐ agent acting as the binder between UMP and silk fabric [53].

**Table 1.** Color fastness at different cationic reagent concentration

During exhaustion dyeing process, the dyeing uptake of cotton fabric without modification was very low. Via cationic reagent modification, the uptake of the cationic fabric was in‐ creased significantly. Cationic reagent with higher proportions increased the number of pos‐

For example, the cationic polymerization modifier was used to modify the charge of cotton fiber, and this could enhance the uptake of UMP and K/S value with different cationic re‐ agent concentration (Figure 5). The application of cationic polymerization modifier on fibers for cationic modification could reduce the production cost, reduce dyeing temperature,

Silk is a natural protein fiber, and the shimmering appearance of silk is due to the triangular prism-like structure of the silk fiber, which allows silk cloth to refract incoming light at dif‐ ferent. But the silk fiber also has some defects, such as the problem of bleaching, the loss of

In order to improve the performance of the silk fiber, silk was modified with cationic disper‐ sant [52]. This improved substantivity of UMP due to the introduction of cationic groups in‐ to the silk fabric, and the balance might be due to the adsorption of cationic reagent on surface of silk fabric reaching saturation values. In this situation, more cationic reagent mol‐ ecules combined with UMP. The bounds between UMP and silk fabric led to a higher K/S values. The different amount of the cationic reagent in pretreatment could impart different amount of positive charge to silk surface, which could affect the K/S values. The UMP was not substantive to silk, the K/S values were low on silk without cationization pretreatment. The K/S values greatly increased and then kept in a balance with the increase of the cationi‐

Furthermore, penetration property and content of ammonium of silk would also restrict to produce the stronger ionic attraction between the cationic fiber and the anionic UMP. As a result, the adsorption of UMP on silk fabric did not change any more accordingly [54]. Wei reported that after modifying with glycidyltrimethylammonium chloride (EPTAC), the reac‐ tions of some amino acids were more rapid than the reaction of glucose. The dyeing ability of modified silk fiber had been improved remarkably. A theory which was called "fixed points" was given to this phenomenon [51]. Wang found that pH in pretreatment affected significantly on the dyeing properties of silk fabric with UMP, because in alkali condition, the chlorohydroxypropyl group of 3-chloro-2-hydroxypropyltrimrthylammonium chloride (CHTAC) converted to an epoxy group and then formed 2, 3-epoxypropyltrimethylammoni‐ um chloride which reacted with the nucleophilic amine group in the silk. And The highest

With the increase of cationic reagent concentration, the rubbing fastness values appeared in‐ creasing trend (Table 1). The washing stain fastness of treated fabric was similarly compara‐ ble to the results without fastness improving reagent treatment because the UMP had no affinity with silk without treatment. Compared with untreated silk, the washing change fast‐

itive charges on the cotton fiber, in turn increased pigment uptake.

shorten the dyeing process and improve production efficiency [49].

**4.2. Dyeing silk fabric with UMP**

90 Eco-Friendly Textile Dyeing and Finishing

pupa protein and the yellowing [50,51].

zation concentration [53].

K/S values could achieve at pH 8 [53].

Cationic pretreatment depended on the extents of reaction between cationic reagent and silk. This might affect the physical properties of the treated fabrics. The tensile strength and elongation at break of fabrics changed with the increase of pH. It was clear that the reaction between cationic reagent and silk took place significantly when pH of the pretreatment solu‐ tion increased. The tensile strength decreased with the peptide chain hydrolyzation when the pH increased. Also the elongation at break kept slightly decreasing. This revealed that the cationic pretreatment has little effect on the physical properties. The bending rigidity and hysteresis of cationization silk had no change compared with untreated silk. It revealed that the cationization treatment had no impact on the soft properties of fabrics. The handle of fabric decreased a little after dyeing, it might be due to the action of fastness improving reagent.

#### **4.3. Dyeing wool fabric with UMP**

The wool fabric was modified by cationic reagent and dyed with UMP which was pre‐ pared with anionic polymer disperser via exhaust method [55]. The influence of pretreat‐ ment conditions such as concentration of cationic reagent, pH value of the bath, temperature and duration of treatment on the dyeing property of the fabric was of impor‐ tance to the drying properties. With the increase of the cationic content, the K/S value en‐ hanced sharply and then kept a constant value when the content on cationic reagent was higher than 10% (Figure 6). The dry and wet rubbing fastness of the wool fabric dyed with UMP via exhaustion was gray scale ratings of 3-4 and 4, respectively. The tensile strength and elongation at break decreased slightly with the increase of bath pH value. The test results of bending rigidity and hysteresis of bending revealed that the wool fab‐ ric had soft handle and good elasticity.

**Figure 6.** The contents of cationic reagent on the K/S value of dyed fabric

#### **4.4. Dyeing cotton fabric with carbon black UMP**

The excellent color and fastness properties make carbon black (CB) particles possible appli‐ cation in textile dyeing. Compared with common sulfur dye, the dyeing process of carbon black UMP can save water and energy due to the shorter dyeing time. However, the disper‐ sion of carbon black UMP in aqueous solutions and adsorption of the particles to cotton fi‐ bers are critical in exhaustion dyeing process, because carbon black UMP is hydrophobic and easily aggregate in aqueous solutions.

**Figure 7.** The dyeing process of carbon black UMP on modified cotton fabric

modified cotton fabric deposited with carbon black UMPs

**Figure 8.** Color assessment of CB dyed cellulose matrixes: (A)K/S values; (B) Video microscope microscope:(a) Cotton fabrics without modification, (b) Carboxyl modified cotton fabric deposited with positive NIMs and carbon black UMPs, (c) Sulfonated modified cotton fabric deposited with positive NIMs and carbon black UMPs, (d) Ammonium

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The results of the K/S presented that the sulfonated cellulose had the higher K/S value of 29.7 than the carboxyl of 28.6 and aminocellulose of 27.9 (Figure 8(A)). The results proved the conclusion about the color depth of the decorated samples. The images (Figure 8(B)) of

On the basis of cotton fabrics modified with cationic reagent, the dyeing process and proper‐ ties of CB dispersions were reviewed (Figure 7). The mechanism of cationic cotton dyed by an exhaustion process using aqueous carbon black UMP dispersions was investigated. Cot‐ ton modified with a cationic reagent enhanced the dyeing properties of aqueous carbon black UMP dispersions. There were higher affinity between carbon black UMP and cationic cotton. CB particles could quickly adsorb on the surface of cationic cotton fibers within 5 min and diffuse into the inner pores and cracks on the surface layer of cationic cotton step by step [56]. The cross sections of cationic-modified cotton fibers dyed with different sizes of CB particles were colorless region, and CB particles were only in the cotton fiber grooves, just as "ring-dyeing". After cationic modification, the cotton fiber could have a dark color for the adsorbability of the anionic CB [13].

The color assessment of CB dyed cellulose is correlative to the amount carbon black UMPs on the cotton via electrostatic force. It made possible to compare the charge density differ‐ ence between nanoparticle ionic materials (NIMs) deposition process and chemical modified process.

Preparation, Characterization and Application of Ultra-Fine Modified Pigment in Textile Dyeing http://dx.doi.org/10.5772/53489 93

**Figure 7.** The dyeing process of carbon black UMP on modified cotton fabric

**Figure 6.** The contents of cationic reagent on the K/S value of dyed fabric

The excellent color and fastness properties make carbon black (CB) particles possible appli‐ cation in textile dyeing. Compared with common sulfur dye, the dyeing process of carbon black UMP can save water and energy due to the shorter dyeing time. However, the disper‐ sion of carbon black UMP in aqueous solutions and adsorption of the particles to cotton fi‐ bers are critical in exhaustion dyeing process, because carbon black UMP is hydrophobic

On the basis of cotton fabrics modified with cationic reagent, the dyeing process and proper‐ ties of CB dispersions were reviewed (Figure 7). The mechanism of cationic cotton dyed by an exhaustion process using aqueous carbon black UMP dispersions was investigated. Cot‐ ton modified with a cationic reagent enhanced the dyeing properties of aqueous carbon black UMP dispersions. There were higher affinity between carbon black UMP and cationic cotton. CB particles could quickly adsorb on the surface of cationic cotton fibers within 5 min and diffuse into the inner pores and cracks on the surface layer of cationic cotton step by step [56]. The cross sections of cationic-modified cotton fibers dyed with different sizes of CB particles were colorless region, and CB particles were only in the cotton fiber grooves, just as "ring-dyeing". After cationic modification, the cotton fiber could have a dark color

The color assessment of CB dyed cellulose is correlative to the amount carbon black UMPs on the cotton via electrostatic force. It made possible to compare the charge density differ‐ ence between nanoparticle ionic materials (NIMs) deposition process and chemical modified

**4.4. Dyeing cotton fabric with carbon black UMP**

92 Eco-Friendly Textile Dyeing and Finishing

and easily aggregate in aqueous solutions.

for the adsorbability of the anionic CB [13].

process.

**Figure 8.** Color assessment of CB dyed cellulose matrixes: (A)K/S values; (B) Video microscope microscope:(a) Cotton fabrics without modification, (b) Carboxyl modified cotton fabric deposited with positive NIMs and carbon black UMPs, (c) Sulfonated modified cotton fabric deposited with positive NIMs and carbon black UMPs, (d) Ammonium modified cotton fabric deposited with carbon black UMPs

The results of the K/S presented that the sulfonated cellulose had the higher K/S value of 29.7 than the carboxyl of 28.6 and aminocellulose of 27.9 (Figure 8(A)). The results proved the conclusion about the color depth of the decorated samples. The images (Figure 8(B)) of the samples before and after the dyeing showed that the color depths of the dyed carboxyl and ammonium fabrics were not as deep as the sulfonated cellulose fabric, which further confirmed the color depth conclusion. Especially for the image of the ammonium sample, the fabric surface was uncoated with carbon black UMP, and there were some starred white flake on the fabric.

From Figure 9, when the temperature was lower than 65 °C, the dyeing rate was quite low, and the adsorption of pigments was unstable, while the temperature was higher than 65 °C, the dyeing rate increased significantly with the dyeing time prolonging. A higher dyeing temperature would shorten the dyeing time. As the temperature was higher than 95 °C, the dyeing time was only 15 min. The reason was that in a low temperature condition, the acryl‐ ic molecular chains were not moving and the adsorption only took place in the surface of

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fiber. The pigments adsorbed to the yarns were easily re-dissolved into the dye bath.

**Figure 9.** Effects of dyeing temperature on dye-uptake of acrylic yarns

of cationic dye is attempted and assessed (Figure 10).

its stable chemical structure.

In order to evaluate the light fastness of acrylic yarns dyed by cationic dye, the light fastness

Cationic UMP presented better light fastness than that of the cationic dye. Acrylic yarns dyed by cationic UMP presented higher stability to light than that dyed by cationic dye. The main reason was that the chromophoric group of pigment was more difficult to destroy for

#### **4.5. Dyeing cotton fabric with cationic UMP**

Surface treatments are effective for UMP because its surface contain polar or polarized func‐ tional groups, which can serve as adsorption sites for the hydrophilic or lipophilic groups of the surfactants [1]. The cationic UMP dispersion has great prospects in cellulose dyeing, inkjet printing, and so on. Compared with the anionic and non-ionic UMP, the cationic UMP has stronger combining force with cellulose substrate, better K/S value, and vividness, thus it can increase the uptake of the UMP, reduce the environment pollution and improve the quality of final products.

For the specific structure, there are a lot of the characteristics on Gemini cationic dispersant. The Zeta potential of the Gemini cationic UMP is higher than that of the ordinary cationic UMP. Therefore, it is easier to color. The dry and wet rubbing fastness is good with both Gemini cationic UMPs after the film fixation (Table 2). With the dispersant dodecyltrimethy‐ lammonium, the dyeing of Gemini cationic UMPs exhibits deeper K/S value and the fabric is easier to be colored. The adsorption capacity of the Gemini cationic UMPs to cotton fabric is stronger, and can cover more fiber surface. Cotton fabric shows negative in a water solution, which has a weak charge bonding force with cationic UMPs. The more cationic UMPs con‐ taining electropositive, the easier the cotton fabric adsorbing the UMPs [16].


**Table 2.** K/S value and fastness of Gemini cationic UMP dispersion on cotton

#### **4.6. Dyeing acrylic yarns with cationic UMP**

Acrylic fibers can be dyed by cationic UMPs, and the electrostatic attraction between UMPs and acrylic fibers is beneficial to the dyeing properties, especially its light fastness property. Compared with anionic and nonionic UMP systems, the cationic UMPs could bond with the acrylic fibers by electrostatic attraction. Therefore, the UMP presented a better dyeing result and a higher utilization ratio [57].

The dye bath pH presented great influences on cationic UMP dispersion stability during dyeing acrylic fiber with cationic UMP. The increase of UMP dosage resulted in lower dyeuptake and more brilliant colors, and dyeing acrylic yarns with UMP (40%, o.w.f) could reach the maximum K/S value. The K/S value of acrylic yarns reduced after adding adhe‐ sives, compared to the cationic dyes, the light fastness was improved significantly [58].

From Figure 9, when the temperature was lower than 65 °C, the dyeing rate was quite low, and the adsorption of pigments was unstable, while the temperature was higher than 65 °C, the dyeing rate increased significantly with the dyeing time prolonging. A higher dyeing temperature would shorten the dyeing time. As the temperature was higher than 95 °C, the dyeing time was only 15 min. The reason was that in a low temperature condition, the acryl‐ ic molecular chains were not moving and the adsorption only took place in the surface of fiber. The pigments adsorbed to the yarns were easily re-dissolved into the dye bath.

the samples before and after the dyeing showed that the color depths of the dyed carboxyl and ammonium fabrics were not as deep as the sulfonated cellulose fabric, which further confirmed the color depth conclusion. Especially for the image of the ammonium sample, the fabric surface was uncoated with carbon black UMP, and there were some starred white

Surface treatments are effective for UMP because its surface contain polar or polarized func‐ tional groups, which can serve as adsorption sites for the hydrophilic or lipophilic groups of the surfactants [1]. The cationic UMP dispersion has great prospects in cellulose dyeing, inkjet printing, and so on. Compared with the anionic and non-ionic UMP, the cationic UMP has stronger combining force with cellulose substrate, better K/S value, and vividness, thus it can increase the uptake of the UMP, reduce the environment pollution and improve the

For the specific structure, there are a lot of the characteristics on Gemini cationic dispersant. The Zeta potential of the Gemini cationic UMP is higher than that of the ordinary cationic UMP. Therefore, it is easier to color. The dry and wet rubbing fastness is good with both Gemini cationic UMPs after the film fixation (Table 2). With the dispersant dodecyltrimethy‐ lammonium, the dyeing of Gemini cationic UMPs exhibits deeper K/S value and the fabric is easier to be colored. The adsorption capacity of the Gemini cationic UMPs to cotton fabric is stronger, and can cover more fiber surface. Cotton fabric shows negative in a water solution, which has a weak charge bonding force with cationic UMPs. The more cationic UMPs con‐

**Sample K/S value Dye rubbing fastness Wet rubbing fastness**

Traditional pigment 42.64 3-4 2

UMP 51.99 4 2

Acrylic fibers can be dyed by cationic UMPs, and the electrostatic attraction between UMPs and acrylic fibers is beneficial to the dyeing properties, especially its light fastness property. Compared with anionic and nonionic UMP systems, the cationic UMPs could bond with the acrylic fibers by electrostatic attraction. Therefore, the UMP presented a better dyeing result

The dye bath pH presented great influences on cationic UMP dispersion stability during dyeing acrylic fiber with cationic UMP. The increase of UMP dosage resulted in lower dyeuptake and more brilliant colors, and dyeing acrylic yarns with UMP (40%, o.w.f) could reach the maximum K/S value. The K/S value of acrylic yarns reduced after adding adhe‐ sives, compared to the cationic dyes, the light fastness was improved significantly [58].

taining electropositive, the easier the cotton fabric adsorbing the UMPs [16].

**Table 2.** K/S value and fastness of Gemini cationic UMP dispersion on cotton

**4.6. Dyeing acrylic yarns with cationic UMP**

and a higher utilization ratio [57].

flake on the fabric.

94 Eco-Friendly Textile Dyeing and Finishing

quality of final products.

**4.5. Dyeing cotton fabric with cationic UMP**

**Figure 9.** Effects of dyeing temperature on dye-uptake of acrylic yarns

In order to evaluate the light fastness of acrylic yarns dyed by cationic dye, the light fastness of cationic dye is attempted and assessed (Figure 10).

Cationic UMP presented better light fastness than that of the cationic dye. Acrylic yarns dyed by cationic UMP presented higher stability to light than that dyed by cationic dye. The main reason was that the chromophoric group of pigment was more difficult to destroy for its stable chemical structure.

cant potential on fabric dyeing, and especially for its environment-friendly characteristics, the development of UMP will present a more sharply speed than that of the dyes. Base on the textile application, the further research interests about UMP are focus on the novel dis‐ persing process to obtain stable UMP system, modification with functional organic or inor‐

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The authors are grateful for the financial support of the National Natural Science Founda‐ tion of China (21174055) and the 333 Talent Project Foundation of Jiangsu Province

Key Laboratory of Eco-Textile, Ministry of Education, School of Textiles and Clothing, Jian‐

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[6] Kelley, A., Alessi, P., Fornalik, J., Minter, J., Bessey, P., Garno, J., & Royster, T.(2010). Investigation and Application of Nanoparticle Dispersions of Pigment Yellow 185 us‐

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ganic materials, developing the multifunction and multipurpose of UMP.

**Acknowledgements**

(BRA2011184).

**Author details**

gnan University, Wuxi, China

and Yunjie Yin

\*Address all correspondence to: wangchaoxia@sohu.com

tion. *University of California Press,*, 12-18.

*nal of Materials Chemistry,*, 17(6), 527-530.

Chaoxia Wang\*

**References**

**Figure 11.** Light fastness of acrylic yarns dyed by cationic dye and ultra-fine pigment
