Effects Of Uv Absorbers On Dyed Cellulosic Fabric Biology Essay

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ABSTRACT

A poor fastness of natural dyes in comparison with synthetic ones is established beyond question. The cause of natural dyes, that, they are not being used for textile goods at commercial scale is due to their poor fastness properties. To face such limitations, the photochemical behavior of natural dye i.e. Turmeric (Curcuma longa L.) and synthetic dyes were investigated. It has been demonstrated that uv-protective effect was strongly dependent on the absorption characteristics of dyes for ultra violet radiations (UVR).Therefore, the improvement of light fastness is sought at the present time. In this respect, various kinds of photo stabilizer (UV-absorbers) were synthesized and applied on to the substrate along with some naturally occurring to prolong the life of coloured species in the natural as well as synthetic dye stuff. At the end, the reactivity of uv-absorbers with the substrate and their properties as auxiliaries increasing UV-protection and dyeing properties were assessed by spectrophotometeric techniques. Significances of uv-absorbers with mordanting agent have been evaluated in different aspects to make the eco-friendly dyes into economical leading commercial dyes.

INTRODUCTION

Dyeing was practiced in ancient times and has undergone many changes in reaching today's development. In the early age, textiles were dyed using plants and animal sources, but with the advent of synthetic dyes, the use of natural dyes in textiles was eliminated since synthetic dyes give variety of shade and colour (Deo and Desai 1999).

Recent studies show that synthetic dyes are non-biodegradable, allergic and some are carcinogenic. Many countries are reluctant to use, import and export the products that are not eco-friendly. Again the world trend is inclined towards natural dyes in textiles as well as in food processing (Sachan and Kapoor 2004).

Good quality dyes must satisfy many requirements in order to be used for colouring of textile materials, one of them is light fastness-an important property determining the fitness of the articles and the durability of their usage (Violeta et al. 1996). Most natural dyes have poor to moderate light fastness, while synthetic dyes represent the full range of light fastness properties from poor to excellent (Daniela and Vilarem 2006). The photochemical behavior of dyes and of the materials which are coloured by them is influenced not only by environmental factors such as light sources and their spectral distribution, temperature, humidity and atmospheric composition, but to a large extent by their chemical structure and the state of the dye in the polymer (Giles et al. 1975).

In last two decades one of the often realized research programmes in the field of textile materials was work on their protective properties against sunlight UV radiation. As it is known radiation of this type emitted by sun in the range between 100 and 400 nm is subdivided into UV-C (100-280 nm), UV-B (280-315 nm) and UV-A (315-400 nm). Higher layers of the atmosphere absorb the radiation of the UV-C range which is most dangerous to living species. Human skin has to be protected against excessive radiation of the UV-B type. It was proved that the excessive radiation of this range is the origin of premature skin ageing, sunburns, allergies and even skin cancer. The UV-A radiation is less dangerous but also its overdose can result in similar effects as described above (Wojciech et al. 2006).

Light fastness of dyed textiles is related to the chemical structure and physical structure of the fiber itself. It is attributed the fading on cellulose to an oxidative process, whereas on protein it have a reductive nature (Cumming et al. 1956). It is stated that indigo is much more light resistant on wool than on cotton (Padfield and Landi et al. 1996). An oxidative pathway is involved in the fading of indigo dyed cotton. As the fading on non-protein substrate is reductive, the indigoid chromophore which is resistant to photoreduction shows high fastness on wool (Roshan et al.1996).

During the photo degradation of azo dyes, an essential role is played also by two reactions (oxidation and reduction) leading to irreversible conversion of azo dyes into the azo group and destruction of the chromophore system. Which is the predominating reaction is determined by the condition of the irradiation and by the medium in which dye is distributed (Violeta et al.1998).

There are normally two ways to improve light fastness of the colour on fabric, to select the dyes with better light fastness and/or to use UV-absorbers to improve light fastness of the dyed samples (Yiqi and Naarani 2007)

UV absorbers are additives used to prevent the photo degradation of polymeric materials by UV-rich sunlight and artificial light. These additives absorb UV radiation and reemit it as fluorescent or infrared radiation. The energy of the excited molecule which causes photo degradation is released as thermal energy (Lappin, 1971). The UV absorbers must have the following characteristics:-

High absorptivity of the radiation between 290 nm and 400 nm,

Stability to long-term light exposure,

Molecular dispersion for optimum screening activity,

Chemical inertness to other additives in the substrate.

Researchers have investigated the usefulness of UV absorbers in reducing colour alteration from two general perspectives: direct application of UV absorbers to fibers and use of UV filtering materials over the light sources (Woeppel and Crews 1990).

So the UV-absorbers are the compounds which have the abilities to absorb the UVR in the sun rays and can protect dyed articles to fade away.

MATERIALS AND METHODS

All the research work was carried out in the dyestuff laboratory, Department of Chemistry and Biochemistry, University of Agriculture Faisalabad. The synthetic work was done in Sandal dyestuff Pakistan Limited and the physical tests were carried out in Noor Fatima Fabrics (Pvt.) limited, Faisalabad. The chemicals used for the research work were of the commercial as well as of analytical grade.

Materials and Instruments

Turmeric (Curcuma longa) rhizomes, Reactive dyes (Reactive red, Reactive scarlet red, Reactive orange), Turkish Blue direct dye.

UV- Visible spectrophotometer (PG Instruments) with assisted software, Spectra flash spectrophotometer (Fastech data V- 2.3 Data Master Colorimeter), Orbital shaker, SDL-Atlas M-228- Rota wash, SDL-Atlas CM-5 Crock meter, Fastech light fastness tester, Vacuum drier, End Pick counter, Grey scales for staining assessment (washing fastness) BSEN: 20105-AO-3, change in color assessment (Light fastness, rubbing fastness) BSEN: 20105-AO-2, Thermostat mantle, High temperature dyeing machine (HT dyeing machine), GSM cutter, Henna digital pH meter and Highly sensitive electrical balance.

Synthesis of UV-Absorbers

UV-Absorber No. 1 (H-absorber)

Prepared suspension of Cyanuric Chloride by adding 11.295g (99%) Cyanuric Chloride into 25ml water and added ice till temperature decreased to 0°C. And further to prepare solution of H-acid, added 19.95g of (80%) H-acid in 40ml water and neutralized with the addition of Na2CO3 very slowly till pH 7 in a separate container. For second condensation 29.56g of VSPE (95%) was dissolved into 50 ml of H2O separately. Adjust the pH of the solution by adding NaHCO3 at pH 7-8 and maintained up to 35 °C.

First Condensation

Solution of H-acid was added to suspension of Cyanuric Chloride slowly along with stirring continuously at temperature 0-5°C. Neutralized the reaction mixture by adding Na2CO3 and stirred well until the condensation was completed.

Second Condensation

During second condensation added the solution of Vinyl sulphone para ester in condensed mixture of cyanuric chloride and H-acid solution at 30-35°C. Neutralized the reaction mixture by adding (20%) Na2CO3. The whole scheme is summarized in figure1.

Fig. 1: Synthesis of H-acid Based UV-Absorber

UV-Absorber No. 2 (J-absorber)

Initially prepared suspension of cyanuric chloride by adding 11.295g (99%) was added into 25ml water at 0°C. Secondly prepared solution of J-acid, added 13.232g of J-acid (90%) in 40ml water and neutralized with the addition of Na2CO3 very slowly till pH 7. For second condensation 29.56g of VSPE (95%) was dissolved separately into 50 ml of H2O. Adjust the pH of the solution by adding NaHCO3 at pH 7-8 and maintained up to 35 °C.

First Condensation

Added solution of J-acid to suspension of Cyanuric Chloride slowly and stirred continuously at a temperature 0-5°C. Neutralized the reaction mixture by adding Na2CO3 and stirred well until the condensation was completed.

Second Condensation

During second condensation added the solution of Vinyl sulphone para ester in condensed mixture of cyanuric chloride and H-acid solution. Second condensation was completed at 30-35°C by heating the resulting mixture along with gentle stirring. Neutralized the reaction mixture by adding (20%) Na2CO3 and stirred well until the condensation was completed..

Fig. 2: Synthesis of J-acid Based UV-Absorber

Natural UV Absorbers

Antioxidants are classified as radical trapping (chain breaker) or peroxide decomposing, metal chelating and might be as synergists. Gallic acid was selected as chain breaker, citric acid as chelating agent and ascorbic acid (Vitamin C) as synergistic agent. Benzophenone was selected as a common UV-absorber (Yong et al., 2000). All he selected UV-absorbers were of analytical grade. The structural formulae of the naturally occurring UV-absorbers are mentioned below;

Fig. 3: Molecular Structures of Selected Natural UV-Absorbers

Synthetic Dyes

Three reactive dyes and direct dyes were selected to check the significances of uv-absorbers on the exhaustion, fixation of dyes and physico-chemical properties of dyed fabric.

Collection of Turmeric (Curcuma longa L.) Rhizomes

It is extracted from the dried rhizome of turmeric. Curcumin is the only natural pigment belonging to the diferuloymethane class and occurs in turmeric in three analogues, termed as Curcumin type I (60%), type II (24%) and type III (14%) which are given below. Chunks of natural turmeric were washed thoroughly with water and dried. These were then crushed into coarse powder form for extraction (Saima et al., 2008).

Fig. 3.8: Molecular Structure of Curcumin Dye 5 (D5)

Crushed turmeric powder was dissolved in water with a material to liquid ratio 1:50 and subjected to heating in reflux condenser apparatus. Turmeric powder suspension subjected to extraction for 60 minutes at boiling temperature (Saima et al., 2008). After completion of adjusted parameters the suspension was cold at room temperature and filtered through filter crucible.

Quality of Fabric

Pure 100% cotton fabric was selected for the purpose of dyeing and for the application of UV-absorbers. The fabric used to dye during the study was availed from quality control lab of Sandal dyestuff industries (pvt) Ltd. Faisalabad. It is very important to have a fabric suitable for any type of dyeing. So, pretreatment quality assurance tests of the fabric for dyeing was assessed according to international standard organization (ISO) including composition, weight of fabric (GSM), construction, pH, absorbency and percentage of desizing (Tegewa rating) of the subjected fabric.

Pre Mordanting of Fabric

For the process of dyeing with natural dye extracted from Curcuma longa the fabric was mordanted before dyeing. In this method cotton was first treated with FeSO4 as mordant concentration of 60% (W/V) on weight of fabric (o.w.f.) at 60 oC for 60 minutes. The material to liquid ratio used for mordanting was 1:15 (Saima et al., 2008). Then the mordanted fabric was dyed under pre-optimized conditions described in table3.1.

UV-Visible Absorption Data

Prepared 10ppm solution of all the samples and scanned in UV-visible spectrophotometer ranging from 190-700 nm, by using quartz cell. From the spectra, λmax of the samples and important peaks were observed and used for further study.

Dyeing of the Fabric

Table below shows all the parameters used for dyeing in exhaust dyeing process.

Table: 1, Optimized dyeing conditions for selected dyes

Dye

Type

Time

(min)

Temperature

oC

Na2SO4

(g/L)

Na2CO3

(g/L)

L : R

Dye 1 (D1)

Reactive Red

30

70 (±2 oC)

20

15

1:30

Dye 2 (D2)

Reactive Orange

30

70 (±2 oC)

20

15

1:30

Dye 3 (D3)

Reactive Scarlet Red

30

70 (±2 oC)

20

15

1:30

Dye 4 (D4)

Direct Blue

45

90 (±2 oC)

20

No alkali

1:30

Dye 5 (D5)

Natural Dye

100

70 (±2 oC)

50

No alkali

1:15

Percentage of Dye Exhaustion

The percentage of dye uptake "U" was calculated by using the following equation. (Eq. 1)…………………..

In equation Ab and Aa represent the absorbance of the dye solution before the dyeing and after time T of dyeing respectively, while "U" represents percentage of dye uptake to the fabric from the dye bath (Julia et al., 2000).

Percentage of Dye Fixation

Samples were washed and K/S values of the extracted samples were measured and the degree of fixation "F" was calculated by the following equation;

(Eq. 2)……………..

Where the subscripts "b" and "a" indicate values before and after the stripping process. The total percentage of the dye uptake fixed on cotton (T) at the end of the dyeing process, can be calculated in accordance with the following equation;

(Eq. 3)……………..

"F' and 'U" were being the degree of fixation and percentage of exhaustion respectively, at the end of dyeing process (Julia et al., 2000).

Application of UV-Absorbers

All the synthetic as well as naturally occurring UV-absorbers were applied on cellulosic fabric. Uv-absorbers were applied on cellulosic fabric with and without (synthetic) selected dyes.

UV-Absorbers on Bleached Cotton

UV-absorbers were applied on fabrics by the exhaust method, similar to; as in the case of monochlorotriazine reactive dyes (Wojciech et al. 2006). UV-absorbers were applied on fabric in different concentrations taking as; 2%, 4%, 6%, 8% and 10% shades on bleached fabric using dyeing formula while taking constant liquor ratio. CIE-Whiteness values were determined at D65/10 (Illuminant) by using spectra flash spectrophotometer. The whole scheme for application of uv-absorbers on white fabric is present in the following table 2;

Table: 2, Application scheme of synthetic UV-absorbers on white fabric

Conc. of UV-Absorbers (%V/V)

(Stock Solution 1% W/V)

2%

4%

6%

8%

10%

Weight of fabric (g)

4

4

4

4

4

L:R

1:30

1:30

1:30

1:30

1:30

Volume of absorber (ml)

8

16

24

32

40

Na2SO4 (g)

2.4

2.4

2.4

2.4

2.4

Na2CO3 (g)

1.8

1.8

1.8

1.8

1.8

Total bath volume (ml)

120

120

120

120

120

UV-Absorbers in Dye Bath

Different concentrations of UV-absorbers were added along with application of dye to the cellulosic fabric using dyeing formula on 4g of cotton fabric pretreated for dyeing. Cotton samples were subjected to dyeing without UV-absorbers were referred as standard samples. During the work three replicates were made for each observation and maximum effectiveness was determined by using statistical techniques like percentage, mean and regression (Steel et al., 1997).

K/S Dyed Samples Treated With Absorbers

The color strength of the dyed fabric treated with UV-absorbers was investigated by using spectra flash spectrophotometer. K/S values were calculated from the reflectance values of dyed fabric using Kubelka-Munk equation, which is given below;

(Eq. 4)……………….

Where "R" is the reflectance of the colored fabric and Ro is the reflectance of the uncolored fabric.

Physico-Chemical Properties

The wash fastness of dyed fabrics was evaluated using ISO-105-CO3. Crock fastness (rubbing fastness) was carried out according to ISO 105-AO-2 test method. Dry the rubbing piece of cotton and was assessed by a comparison with grey scale (Anonymous, 1990). The light fastness of dyed fabric is evaluated by exposing the fabric samples to Mercury ARC. The light fastness of the dyed fabrics was evaluated according to ISO-BO-2 test method.

Results and Discussion

UV-Visible absorption spectra of the absorbers

UV absorbers are organic or inorganic colourless compounds with strong absorption in UV range of Radiation spectrum (Mallik and Arora, 2003). All the absorbers showed detectable peaks in ultra violet region of the scanned spectra. There is no any detectable peak in visible region which confer that all the absorbers are colorless in vision in their lower level of concentration.

Table: 3, Characteristics of applied UV-absorbers

UV Absorber

Source

Percentage purity

λmax (nm)

Important peaks

Ascorbic Acid (A)

Natural

99.5

260

200

Benzophenone (B)

Natural

99

227

217, 239

Citric Acid (C)

Natural

98

224

234, 359

Gallic Acid (G)

Natural

97

220

258

H-absorber (H)

Synthetic

88

239

293, 395

J-absorber (J)

Synthetic

84

272

218, 285

Dye 1 (D1)

Reactive Synthetic

Commercial

524

460, 360, 232

Dye 2 (D2)

Reactive Synthetic

Commercial

478

412, 338, 346

Dye 3 (D3)

Reactive Synthetic

Commercial

490

443, 362, 336

Dye 4 (D4)

Direct Synthetic

Commercial

605

333

Dye 5 (D5)

(Turmeric)Natural

Commercial

390

334, 350

The chemical structure of dye molecule is divided into two parts the main skeleton (chromophore) colour generating and the substituent (auxochrome) color promoting groups (Daniela and Vilarem 2006). So the presence of chromophore is responsible for the absorption of radiations in visible part of the spectrum, while the colored solution of the dyes also absorb radiations in the ultraviolet part of the spectrum as mentioned in the table 3.

Quality of Fabric

The fabric that was selected for the purpose of dyeing and for the application of UV-absorbers it must have to be suitable for any type of dyeing. It is obvious that UVR protecting property of textile goods are dependent on the absorbance and transmission of UV radiations through the particular fabric. It is understood that these properties depends on some factors like thickness, porosity, chemical composition, and the presence of dyes ,their concentration as well as other textiles auxiliaries like finishers and UV-absorbers (Wojciech et al., 2006). So, pretreatment quality assurance tests of the fabric for dyeing produced results are mentioned in table 4

Table: 4, Standard methods and quality of cellulosic fabric to be dyed

Test

Standards

Result

Blending Ratio

ISO-1833

100% Cotton

Construction

ISO-7211

60Ã-54/20Ã-20

GSM

ISO-3801

98 g/m2

pH

ISO-3071

8

Absorbency

AATCC-79

5 cm/min

Percentage of Sizing

AATCC-103

6-7

Application of Synthetic UV absorber

Exhaustion of Absorbers

The Synthesized UV absorbers applied on white fabric and the percentage of exhaustion was measured. Synthesized absorbers are just like reactive dye but they don't have any chromophoric group so unable to produce color to the fabric but they react with cellulosic polymer just like reactive dyes. The absorbers containing reactive groups could form covalent bond with cellulosic matrix, these would be able to maintain their Uv-protecting properties for prolong period of time (Wojciech et al., 2006).

The outcome of presented data shows that even reactively simple derivatives of symmetrical trichloro triazine which are being used as intermediates in industrial synthesis of fiber reactive dyes could be valuable reactive UV-absorbers increasing solar radiation protective properties of uncoloured cellulosic fabric.

Fig. 4; Effect of Concentration of UV-absorbers on their Exhaustion

CIE Whiteness of Treated Fabric

Additives can be used to increase the absorption of ultraviolet damaging radiations (Peter et al., 1998). It is obvious that one of the most expected and important characteristic of uncoloured textile garments is retaining their white colour during use and by applying UV-absorbers. UV absorbers, especially at high concentration are yellowish in color and thus adding absorbers on white fabric through high concentration will change the color of the treated fabric (Yiqi and Naarani 2007). Applied H-acid based (H) absorber is more responsible to decrease the whiteness due to its own yellowish color as compared to J-acid (J) absorber as in Fig.5.

Fig. 4.13; Effect of UV-absorbers on Whiteness of Cotton

Application of Absorbers with Dyes

UV absorbers to the extent of 0.6 - 2.5% are sufficient to provide UV protection to the chromophoric groups of the coloring material (Rienert et al., 1994). Initially the concentration of the absorbers was optimized and that concentrations which yielded high degree of exhaustion and fixation of the dye were selected for further studies. The optimized very dilute concentrations used in exhaust dyeing process are mentioned in table 5. Suitable combination of UV absorbers and antioxidants can yield synergistic effects in exhaustion of dye from dye bath to the fabric material.

Table: 5, Characteristics of dyes and optimized concentrations of UV-absorbers

Dye

Nature

Colour

λmax (nm)

Absorbers and Their Optimized Concentration % V/V (Stock Solution 1% W/V)

(A %)

(B %)

(C %)

(G %)

(H %)

(J%)

Dye 1 (D1)

Reactive

Red

524

6

6

6

6

6

6

Dye 2 (D2)

Reactive

Orange

478

6

6

6

6

6

6

Dye 3 (D3)

Reactive

Blood Red

490

4

4

4

4

4

4

Dye 4 (D4)

Direct dye

Blue

605

4

4

4

4

4

4

Dye 5 (D5)

Natural dye

Yellow

398

6

6

6

6

6

6

Effect of Absorbers on the Synthetic Dye Exhaustion

Different types of absorbers were applied on cotton in "all in" exhaust dyeing method. The results showed that there is significant variation in percentage degree of exhaustion of the dye onto the cotton. Dye uptake increased in all dyes when applied with any type of absorber. Percentage of exhaustion decreases by increasing concentration of the dye. All the absorbers are synergistically increased the exhaustion of the dyes but Benzophenone, J-acid based absorbers are significantly responsible to increase dye uptake. Effect of absorbers on the dye uptake values pf various dyes are shown in figures 6 to 10.

Fig. 6; Effect of Different UV-Absorbers on Exhaustion of Dye 1. Fig. 7; Effect of Different UV-Absorbers on Exhaustion of Dye 2

Fig. 8; Effect of Different UV-Absorbers on Exhaustion of Dye 3 Fig. 9; Effect of Different UV-Absorbers on Exhaustion of Dye 4

Fig. 10; Effect of Different UV-Absorbers on Exhaustion of Natural turmeric Dye 5

Effect of Absorbers on the Synthetic Dye Fixation

Different types of absorbers were applied on cotton in "all in" exhaust dyeing process. Dye fixation increased in all dyes when applied with any type of absorber. Percentage of dye fixed on to the fabric decreases by increasing concentration of the dye. So from the results it can be observed that high percentage of dye shade producing low level of exhaustion as well as fixation. All the absorbers are synergistically increased the fixation of the dyes but Benzophenone, J-acid based absorbers are significantly responsible to increase dye uptake. Effect of absorbers on the dye uptake values pf various dyes are summarized in figures. In case of reactive dye 1 all the absorbers increased the percentage of dye fixation except gallic acid (G) which showed low level of fixation of dye when applied in 5% dye shade. All the other additives catalytically increase dye fixation especially when dye was applied in lower concentration, summarized in figures.

Fig. 11; Effect of Different UV-Absorbers on Fixation of Dye 1. Fig. 12; Effect of Different UV-Absorbers on Exhaustion of Dye 2

Fig. 13;Effect of Different UV-Absorbers on Exhaustion of Dye3 Fig. 14;Effect of Different UV-Absorbers on Exhaustion of Dye4

Fig. 15; Effect of Different UV-Absorbers on Exhaustion of Natural Turmeric Dye 5

During the dyeing of cotton with natural dye the application of absorbers also increased the dye fixing ability in both when applied on pre-mordanted cotton as well as non mordanted fabric. Curcumin has unique conjugated system having two methoxylated phenols and enol form of β-diketone. It exists in keto-enol tautomerism with equilibrium strongly favoring the enol form. The enol structure enables Curcumin to form a firm inter and intera- molecular hydrogen bonding. (Richard et al., 1996).

All the observations revealed that any type of absorbers which were applied increased the exhaustion and fixation of the dyes. Comparatively the dyeing without any UV absorber has low degree of exhaustion and fixation, but when absorbers were added in dyeing bath. They synergistically more or less increased the dyeing properties and have some degree of effect to promote the interaction of dyes with the fabric polymeric structure.

Color Strength (K/S) of Dyed Samples Treated With UV-Absorbers

So the changes of shade due to the addition of UV absorbers indicate that a calibration of shades is necessary for the production of dyed as well as white finishing fabric (Yiqi and Naarani 2007). Both the absorbers have positively affect the attachment of the dye molecule to the fabric but these are responsible to deprive the chromophoric group for absorption of visible part of the radiation, that's why they decrease the color strength slightly is observed. Addition of mostly absorbers increased the K/S values of the treated samples.

Fig. 16; Effect of Different UV-Absorbers on K/S of Dye 1 Fig. 17; Effect of Different UV-Absorbers on K/S of Dye 2

Fig. 18; Effect of Different UV-Absorbers on K/S of Dye 3 Fig. 19; Effect of Different UV-Absorbers on K/S of Dye 4

Fig. 20 ; Effect of Different UV-Absorbers on K/S of Dye 5

The K/S values of the dyed samples of Curcumin extracted from turmeric are represented in figure. The lower color strength is due to the alkaline degradation of Curcumin chromophore into water soluble products like; vanilic acid, ferulic acid, vaniline and other degraded products which give dull redder shade (Tonnesen et al., 1986). The premordanting method produces a high depth of shade in comparison with the post mordanting mode of application of natural dyes (Deo and Desai, 1999).

Fastness Properties of Treated and Untreated Samples with UV-Absorbers

The colored fatness of a colored textile is defined as its resistance to changes in color when subjected to a particular set of conditions.

Fastness Properties of Treated Samples of Dye 1 (D1)

When dye 1 is applied on to the fabric, the wet crock fastness not showed appreciable results in lower concentration shade (1%) as compared to non treated dye with absorbers. Fading of the dye is reduced and staining of the washed dye onto the adjacent fabric is not altered by the addition of absorbers in low concentration of the dye. As a result dark shades show high level of light fastness but when the same dyes are applied on fabric in light shades these are faded away easily by the action of UV radiations. The results showed the addition of UV absorbers in the dye bath including light shades enhanced the light fastness of the dyed article.

Table: 6, Fastness properties of dye 1 treated with UV-absorbers

Dye 1 (1%) with Absorbers

Wet Crock Fastness

Washing Fastness

Light Fastness

Dye 1 (5%) with Absorbers

Wet Crock Fastness

Washing Fastness

Light Fastness

Fading

Staining

Fading

Staining

D1

4-5

3-4

4

4

D1

3

3

3

4-5

D1A1

4-5

4-5

4

4-5

D1A5

3

3

3

4-5

D1B1

4-5

4-5

4

4-5

D1B5

3-4

3-4

4

4-5

D1C1

4-5

4-5

4

4-5

D1C5

3

4

4

4-5

D1G1

4-5

4-5

4

4-5

D1G5

3

4

4

4-5

D1H1

4-5

4

4

4+

D1H5

3

3-4

4

4-5

D1J1

4+

4-5

4

4+

D1J5

3

4

4

4-5

Fastness Properties of Treated Samples of Dye 2 (D2)

The given data of results show that light fastness of light shade is of lower rating but of higher concentration shade producing excellent light fastness rating with or without any addition of UV absorber.

Table: 7, Fastness properties of dye 2, treated with UV-absorbers

Dye 2 (1%) with Absorbers

Wet Crock Fastness

Washing Fastness

Light Fastness

Dye 2 (5%) with Absorbers

Wet Crock Fastness

Washing Fastness

Light Fastness

Fading

Staining

Fading

Staining

D2

4

4

3-4

3-4

D2

3

4

2-3

4-5

D2A1

3-4

4-5

4

4-5

D2A5

3

4-5

3

4-5

D2B1

4

4-5

4

4

D2B5

3

4-5

3

4-5

D2C1

4

4-5

4

4

D2C5

3

4-5

3

4-5

D2G1

4

4-5

4

4

D2G5

3

4-5

3

4-5

D2H1

4

4-5

4

4+

D2H5

3

4-5

3

4-5

D2J1

4+

4-5

4

4

D2J5

3+

3-4

3

4-5

Fastness Properties of Treated Samples of Dye 3 (D3)

The results obtained after the application of dye 3 on to the fabric, revealed that the wet crock fastness not showed appreciable results in lower concentration shade (1%) as compared to non treated samples. The crock (rubbing) fastness remains unchanged in most cases of addition of additives in dyeing bath for both the studied shades

Table: 8, Fastness properties of dye 3 treated with UV-absorbers

Dye 3 (1%) with Absorbers

Wet Crock Fastness

Washing Fastness

Light Fastness

Dye 3 (5%) with Absorbers

Wet Crock Fastness

Washing Fastness

Light Fastness

Fading

Staining

Fading

Staining

D3

3-4

4-5

4

4

D3

3

4-5

4

4-5

D3A1

3-4

4-5

4-5

4-5

D3A5

3

4-5

4

4-5

D3B1

3-4

4-5

4-5

4+

D3B5

3

4

4-5

4-5

D3C1

3+

4-5

4-5

4-5

D3C5

3

4-5

4

4-5

D3G1

3-4

4-5

4-5

4-5

D3G5

3

4-5

4

4-5

D3H1

4

4-5

4-5

4-5

D3H5

3-4

4-5

4

4-5

D3J1

3-4+

4-5

4-5

4-5

D3J5

3-4

4-5

4

4-5

Fastness Properties of Treated Samples of Dye 4 (D4)

Addition of absorbers is fruitful for application more favorably in lower concentration of dye. The given data of results show that light fastness of light shade is of lower rating but of higher concentration shade producing excellent light fastness rating with or without any addition of UV absorber.

Table: 9, Fastness properties of dye 4 treated with UV-absorbers

Dye 4 (1%) with Absorbers

Wet Crock Fastness

Washing Fastness

Light Fastness

Dye 4 (5%) with Absorbers

Wet Crock Fastness

Washing Fastness

Light Fastness

Fading

Staining

Fading

Staining

D4

4-5

3

4

3-4

D4

3-4

2-3

3

4

D4A1

4-5

3-4

4

3-4

D4A5

3-4

3

3-4

4-5

D4B1

4-5

3-4

4-5

3-4

D4B5

3-4

3

3-4

4+

D4C1

4-5

4

4-5

4

D4C5

3-4

3

3-4

4-5

D4G1

4-5

3-4

4-5

4

D4G5

3-4

3

3-4

4

D4H1

4-5

4

4-5

4+

D4H5

4

3

3-4

4+

D4J1

4-5

3-4+

4-5

3-4+

D4J5

4

3

3-4

4

Fastness Properties of Treated Samples of Dye 5 (D5)

The fastness of a mordant dye depends on the mordant and the mordanting method. As different dye metal complexes are formed which may cause difference in their stability to light and also because the metal have a positive or negative catalytical effect on the photochemical degradation of the dye (Gupta, 1999). For better fastness to light radiations and washing fastness the use of mordant is essential for most of natural dyes. The effect of mordant is to assist the adsorption of the dye molecule and also to promote good bonding of coloring component with fiber as a bridge which helps to bond the dye and fiber at molecular level (Feng et al., 2007). The improvement in washing fastness of the mordanted samples is due to decrease in dye solubility (Tsatsaroni and Eleftheriadis 1994). Its yellow color is faded away after exposure to UV radiations. (Shinyong and Yiqi 2005). Some of inherent fluorescent properties in Curcumin the active life period of these molecules is longer and chances of collision with oxygen in air and radiations that make them more feasible to photochemical oxidation.

Table: 10, Fastness properties of dye 5 treated with UV-absorbers

Dye 5 With Absorbers But Non Mordant

Wet Crock Fastness

Washing Fastness

Light Fastness

Dye 5 With Mordant And Absorbers

Wet Crock Fastness

Washing Fastness

Light Fastness

Fading

Staining

Fading

Staining

D5

4

2

4

2

D5m

4

2-3

4

2-3

D5A

4

4

4

2-3

D5Am

4

3

4

2-3

D5B

4-5

3-4

4

2-3

D5Bm

4-5

4

4-5

2-3+

D5C

4

3

4

2-3

D5Cm

4-5

3

4

2-3

D5G

4

3

3-4

2-3

D5Gm

4

3-4

4

3

D5H

4

3-4

4

3-4+

D5Hm

4-5

3-4

4

3

D5J

4-5

3

4

3-4

D5Jm

4-5

3

4

3

COCLUSION

Dyeing was practiced in ancient times. In the early age, textiles were dyed using plants and animal sources, but with the advent of synthetic dyes, the use of natural dyes in textiles was eliminated since synthetic dyes give variety of shade and colour.

Recent studies show that synthetic dyes are non-biodegradable, allergic and some are carcinogenic. Many countries are reluctant to use, import and export the products that are not eco-friendly. On the other hand natural dyes don't have excellent fastness properties at all; especially turmeric a natural yellow colour produces poor washing and light fastness rating. Such problems resist using natural dyes as economical source at industrial level. Not even natural dyes but most of the reactive dyes have moderate to good fastness properties. To overcome such limitations of industrial dyes some additives were synthesized and applied along with some naturally occurring. These additives applied on the white fabric and also along with natural and synthetic dyes especially to protect the textile articles from solar ultraviolet radiations. In this regard, the induced UV absorbers and their reducing effect of photo degradation of color was subject of interest. Along with improvement in light fastness, some other physico-chemical properties like crock and washing fastness were also studied. The whole study project concluded that the applied UV absorbers significantly increased the light and wash fastness properties of all the natural and synthetic dyes but these are unable to enhance the crock (rubbing) fastness at appreciable extent. During study it was the keen result that synthetic as well as natural absorbers improve the exhaustion and fixation of all the dyes synergistically during dyeing. The significances of these UV absorbers are helpful to increase the fastness properties of industrially used dyes including reactive, direct and natural curcumin dyes.

So the result showed that the application of UV absorbers is very helpful to increase exhaustion, fixation and fastness properties of treated fabric with UV absorbers. Protection against the UVR is very helpful to avoid the skin and dyed article from damaging ultraviolet radiations, which is economically and hygienically handy in textiles.

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