Abstract:


Mesta jute fiber has been modified with sodium sulfite in presence of MEA (monoethanolamine) and bleached with hydrogen peroxide. Bleached modified jutehas been dyed with Reactive Red HE3B, Reactive Blue R,Direct Green BL and Direct Red 6BL. The light and wash fastness, multifabricstaining, and breaking strength of dyed bleached modified mesta jute has beenstudied and compared with that of dyed bleached raw mesta jute. Modificationsignificantly improves whiteness index, light and wash fastness, less staining.On exposure to UV light loss in breaking strength of dyed modified bleachedmesta jute with Reactive Red 120 is minimum in comparison with other dyes.


Key Words: Modification, mesta jute, bleaching, colorfastness, breaking strength


Introduction


Reactive and direct dyes are available synthetic dyesamongst the commercial dye range. They are still the brightest and the mostbrilliant in hue of the synthetic dyes and widely used for the dyeing ofcotton, jute, kenaf, flax. Dyes of this type are anionic in character and ingeneral owe their water solubility to the presence of sulfonate groups (HSO3).However, since jute itself adopts an anionic surface charge in water, thesedyes have low intrinsic affinity for the fiber. The repulsive charge betweendye and jute fiber can be overcome by adding an electrolyte such as sodiumchloride or sodium sulfate, which has the effect of screening the surfacecharge on the fiber [1]. Jute fiber possesses good affinity than cotton withdirect dyes due to the presence of lignin. But from the practice, it has beenobserved that they possess very poor color fastness on jute. A number ofattempts have been made to modify the jute fiber using different type of metalsalt, vinyl monomers to improve of the color fastness properties [2-7]. A fewefforts were made to improve the light fastness which is the major problem for jute when it is exposed to sun light [8]. But no researcher tried to delignify jutefiber and sulfonation of lignin in jute fiber for the improvement of the colorfastness properties.


In the present investigation an effort was made to improve bleaching and color fastness properties of reactive and direct dyes applying on bleachedmodified mesta jute fiber. An assessment of whiteness index, light and washfastness, and breaking strength of dyed bleached modified mesta jute has beendone. The results have been compared with that of bleached raw mesta jutefiber.


Experimental


Materials


Bleached raw and modified mesta jute fibers were used as materialfor the investigation. Direct Red 6BL (C.I. 35780), Direct Green BL (C.I. 34045), Reactive Red HE3B (C.I. 25810) and Reactive Blue R (C.I. 61200) were obtained from commercialsources and were used as received. All other chemicals used were of C.P. gradeand were used as such without further purification.


Modification


Mesta jute fiber was modified with 15% (owf) of sodiumsulfite in presence of 0.5 %( owf) MEA (monoethanolamine) as a delignifyingagent at 150C for 3.0 hrs [9].


Scouring and bleaching


In order to remove the wax, oil, resin and coloring matterfrom the fiber, first, all fibers were scoured by standard method with asolution of 4 % sodium carbonate, 1% sodium hydroxide and 0.5 % wetting agentat 75 C for 0.5 hour [1]. It was then bleached by standard method inlaundering ometer with 2.1 % hydrogen peroxide together with 6 % sodiumsilicate and 0.5% sodium carbonate to maintain pH 11 initially. Percentage wasbased on the weight of the material, in the liquor ratio of 15:1. Bleaching wascontinued for 1.5 hour at 95C. It was then washed and dried [10].

 

Dyeing


The dye bath was prepared by 2% of Direct Red 6BL and Direct Green BL, and 3% Reactive Red HE3B and Reactive Blue R separately with 0 .1% wetting agent based on the weight of the material and 80g/l sodium sulfate and 10g/l soda ash, in the liquor ratio was 30:1. Sample was added to each dye bath and dyeing was commenced after 5 min at room temperature. The temperature was then raised to 90 C at a rate of 1.5 C/min. Dyeing was continued at this temperature for 50 min before cooling to 70 C at a rate of 3 C/min. The dyed sample were rinsed thoroughly in cold and hot water and finally distillated water and then dried in air oven[11].


Fastness testing


The color fastness of the dyed fibers to laundering and light were assessed using AATCC test methods [12]. Fastness to laundering was evaluated by AATCC Method 61-1996 (2A) using an Atlas Launder Ometer . Multifibre fabric was employed for the evaluation of staining on cotton. Fastness to light was evaluated by AATCC Method 16E using an Atlas CI 3000+ Xenon Weather ometer. The samples were each exposed to 80 AATCC Fading Units, corresponding to 84.8 h continuous exposure under a xenon lamp at an irradiance power of 1.1 W/m2/nm at 420 nm. The grey scale was used for color change and for staining, giving color difference.


Breaking Strength testing


Breaking strength of dyed bleached modified mesta jute fiber was tested according to ASTM method D 2524-94.


Results and Discussion


The whiteness index of bleached modified mesta jute is summarized in Table I. It is observed from the Table I that the whiteness index of bleached modified mesta jute is significantly higher than that of bleached raw mesta jute but affected breaking strength. This can be confirmed to the increase in the temperature the presence of hydrogen atoms in the polymer molecule greatly decreases the energy of the C-C bond. When the fiber is heated the energy of thermal motion causes fluctuation of the chemical bond, which causes the weaking of bond in the cellulose chain. As a result, the breaking strength of the fiber decreases[13]. The color change of dyed bleached raw and modified mesta jute fibers after laundering is summarized in Table II in terms of the grey scale rating. In all cases, bleached modified mesta jute was significantly better than that of bleached raw mesta jute fiber. This can be explained by the fact that the van der waals forces linking between the direct dyes and modified mesta jute fiber, and covalent bond between reactive dyes and bleached modified mesta jute are much stronger than the raw mesta jute fiber. It is observed from the Table II that wash fastness of Reactive blue R was better than other dyes. Table III showed the staining on the adjacent undyed multi fabrics caused by the dyed fibers during laundering. The mesta jute fiber treated with sodium sulfite in presence of monoethanolamine and dyed with reactive and direct dyes produced less staining over untreated mesta jute fiber, since the strong ionic interaction between the dye and sulfonic group reduced the removal of dye from the fibers.


Table IV summarizes the light fastness properties of dyed fibers. In all cases bleached modified mesta jute was better than that of bleached raw mesta jute. This happens, probably, due to the presence higher amount of lignin in bleached raw jute fiber. The high reactive groups present in lignin are phenolic hydroxyl groups [14]. Lignin is highly sensitive to the action of light. When UV-light falls upon dyed jute fiber, the phenolic hydroxyl groups of lignin in mesta jute created free radicals. These free radicals undergo transformation into quinoid structures and showed yellowing on surface of fiber thus causing easily fading of dyed bleached raw mesta jute fiber [15]. Conversely, dyed bleached modified mesta jute fiber contains minor amount of lignin and above 60% phenolic hydroxyl groups were blocked by -HSO3. Therefore after sulfonation when the fiber is subjected to light in presence of atmospheric oxygen, photo-yellowing can not be accelerated as much as bleached raw mesta jute fiber.


It is observed form the Table V that the percent loss in breaking strength of dyed bleached modified mesta jute was lower than that of bleached raw mesta jute for all of dyes. The plausible explanation of such behavior is that the photo-oxidative degradation is initiated by lignin which acts as a sensitizer and causes degradation of cellulose in all possible manners through the formation of hydrogen peroxide [16]. The reaction involved in photo-chemical degradation of mesta jute is mainly oxidative in nature and on prolong exposure to UV light the constituent of cellulose chain are gradually attacked and ultimately broken down into the smaller fragments, as a result, breaking strength of mesta jute decreased.

 

Conclusions


The whiteness index of bleached modified mesta jute was significantly higher than that of bleached raw mesta jute but slightly affect breaking strength. The dyeing fastness properties of bleached modified mesta jute have been evaluated using Direct Red 6BL, Direct Green BL, Reactive Red HE3B and Reactive Blue R. The wash fastness of dyed bleached modified mesta jute had better impact than that dyed bleached raw mesta jute fiber .The sulfite treatment of mesta jute providing strong ionic interaction with the dye and reducing its tendency to be washed out on laundering. The light fastness of dyed bleached modified mesta jute was much better than that of dyed bleached raw mesta jute. The modification of mesta jute protected photo-fading chemically attached of sulfonic group in the phenolic hydroxyl groups of lignin. The loss in breaking strength of dyed bleached modified mesta jute was significantly lower than that of dyed bleached raw mesta jute.


References


1)    Trotman, E.R.; Dyeing and Chemical Technology of Textile Fibres. Charles Griffin and Company Ltd., England. 6th edn. 1984, 285, 223.

2)    Patro, P.S. Textile Dyer and Printer, 1971, 4, 57.

3)    Salam, M. A., Farouqui, F. I. and Hossain, I.; J. of the Bangladesh Chem. Soc., 2001, 2, 14.

4)    Sayeed, M.A.; Islam, N.; Farouqui. F.I and Faruq, M.O; The Rajshahi University Studies, 1987, 15, 1.

5)    Hossain,I.; Farouqui, F.I; Textile Dyer and Printer, 1990, 23, 28.

6)    Sikdar,B.; Basak, R. K; J. of Appl. Polym. Sci., 2003,55,1673.

7)    Mary, C.; J. of Appl. Polym, B. C,. Sci., 2003, 27, 4525.

8)    Kamal Uddin, M.; Ashraf Hussain, M.; Atiar Rahman, Kh.; Alamgir Sayeed, M.M; J. of Biological Sci., 2002, 2 , 378.

9)    Virkola, N. E; Kettunon, J.; Pusa R.; Tappi, 1981, 64, 103.

10)  Ibrahim H; the Indian Textile J., 2002, 9, 280.

11)  Salam, M.A.; Hossain,I. ; Farouqui, F.I; The Indian Textile Journal, 2002, 6, 27.

12)  AATCC Technical Manual, 2000, 75.

13)  Salam M.A.; J. of Appl. Polym. Sci., 2006, 99, 3603

14)  Chatterjee, S.M.; Reactivity of jute, The Indian Textile J. , 1975, 8,149.

15)  Callow and Speakman, J. Soc. Dyer. Col., 1949, 65, 758.

16)  Egerton, G.S.; The mechanism of photo-chemical degradation of textile materials, J. Soc. Dyers and Colourists, 1949, 65, 764.


Tables



Table I: Bleaching properties of modified mesta jute


Sample

Whiteness Index

(CIE)

Breaking Strength

(g/denier)

Elongation

(g/denier)

Bleached raw mesta jute

33.0

1.64

1.30

Bleached modified mesta jute

68.0

1.58

1.65


Table II: Wash fastness of dyed bleached modified mesta jute


Sample Wash fastness (Gray scale rating)
Reactive Red HE3B Reactive Blue R Direct Red 6BL Direct Green BL

Bleached raw mesta jute

2.0 3.0 2.0 2.5

Bleached modified mesta jute

4.0 4.5 3.0 3.0



 

Table III: Staining on cotton fabric caused by dyed bleached modified mesta jute fiber


Sample Gray scale rating
Reactive Red HE3B Reactive Blue R Direct Red 6BL Direct Green BL

Bleached raw mesta jute

2.5 2.0 3.5 2.5

Bleached modified mesta jute

2.0 1.0 2.5 1.5


Table IV: Light fastness of dyed modified bleached mesta jute


Exposure

Period

(AFU)

Sample

Light fastness (L value)

Reactive Red HE3B

Reactive Blue R

Direct Red 6BL

Direct Green BL


40

Bleached raw mesta jute

2

2

4

3

Bleached modified mesta jute

3

3

5

5


Table V: Breaking strength of dyed modified bleached mesta jute


Exposure

Period

(AFU)

Sample

Breaking Strength(g/denier)

Reactive Red HE3B

Reactive Blue R

Direct

Red 6BL

Direct Green BL


0

Bleached raw mesta jute

1.52

1.60

1.65

1.58

Bleached modified mesta jute

1.45

1.50

1.53

1.50


40

Bleached raw mesta jute

1.14

1.28

1.25

1.19

Bleached modified mesta jute

1.27

1.35

1.30

1.25

 

About the Authors:


The authors are associated with Department of Applied Chemistry & Chemical Technology, University of Rajshahi, Rajshahi, Bangladesh.

 

 

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