I ndian Journal of Fibre & Texti le Research Vol. 3 1 , December 2006. pp. 559-564

Dyeing of wool and silk with Punica granatum Debasish Das"

Inst itute of Jute Technology. 35 Bal lygunge Circular Road, Kolkata 700 0 1 9, I ndia

Subhash Chandra Bhattacharya

Department of Chemistry, Jadavpur Un iversity. Kolkata 700 032, I ndia

and

Sankar Ray Maul ik

Visva Bharati University. l3olpur. Sant iniketan 73 1 235, I ndia

Received 22 A llgllSI 2005; revised received al/{I accepted 21 Novell/bel' 2005 The application of dye obtained from Pllllica grw/{/tl/lll fruit rind on wool and si lk fabric i n the presence and absence of

environment-friendly Illordanting agents has been studied. The dyeing of s i lk and wool with pomegranate solution is found to be effecti vely accomplished at pH 4.0. Pre- and post-mordanting employi ng ferrous sulphate and aluminium sulphate improve the colour uptake, l ight fastness and colour retention on repeated washi ng. The use of such mordants, however. does not improve wash fastness property of dyed substrates.

Keywords: Dyeing, Mordant ing. Pllllica grallatlllll. Silk, Wool IPC Code: I nt. CI .8 C09B6 1 /00, D06P3100

1 Introduction Pomegranate is the name given to a sweet ju icy

fruit obtained from the culti vated species PUll ica granatulIl and PlInica profopunica . Pllnica granatulIl is cultivated in tropical and subtropical parts, whereas Punica protopunica i s found in the Socotra I sland. '

Pomegranate is appreciated for its cool refresh ing juice with sweet acidic taste and also for its medic inal properties?.) The skin of such frui t i s red to brown in colour and colouration of text i le can be done using such colour of the skin, when extracted with water.4-6

Fruit rind contains nearly 25% of an ellagi-tannin­flavogallo\ .6 The present paper reports the appl ication of such dye obtained from pomegranate frui t rind on wool and silk fabrics in the absence and presence of environment-friendly mordanting agents.

2 Materials and Methods

2.1 Materials

Plain weave bleached wool and loom state s i lk fabrics, having 236 ends/dm & 430 ends/dm, 204 picks/dm & 2 12 picks/dm, and 1 50 g/m" & 50 g/mC i n weight respectively were used for the study. Acryl ic yarn, obtained from Mis Consolidated Fibres and

"To whom all the correspondence should be addressed. E-mai l : ijt@caI2 .vsnl .net. in/s_r_moul ik@yahoo.co. in

Chemicals Ltd. West Bengal, India and made of copolymer having 9 1 % acrylonitrile, 8 .5% vinyl acetate and 0.5% sodium styrene sulphonate was also used. Punica granatulIl dye, obtained from Mis ALPS Industries Ltd. India, was used after purify ing it by dissolv ing in methanol , fol lowed by filtration and recrystaI J i sation. All the chemicals used in the study were of laboratory reagent grade.

2.2 Methods

2.2.1 Deglllllming alld Bleaching of Silk

The loom state s i lk fabric was degummed at 90°C for 1 .5 h in an aqueous solution containing soap (6.0 giL) and sodium carbonate (2.0 giL). The degummed s i lk sample was bleached at 85°C for 1 h in a solution contain ing hydrogen peroxide (0.9%), non-s i l icate stabi l izer (0. 1 5%) and sodium carbonate (0. 1 %) . Material-to-l iquor rat io for both degumming and bleaching operations was maintained at 1 :20. Bleached sample was washed at 70°C for 10 mm, cold washed and finally dried.

2.2.2 Dyeillg of Substrales with POlllegranale SOllilioll

2.2.2. / /11 Ab.l'ellce o/Mordollt

Si lk and wool fabrics and acryl ic yarn were dyed with pomegranate solution ( 1 0% owf) at a material­to-liquor ratio of 1 :50. The dye bath temperature was

560 INDIAN J . FIBRE TEXT. RES . , DECEMBER 2006

kept at 90°C for 1 h . The pH of the dye bath was set at different specified levels ranging from 2 to 1 0. Hydrochloric acid, acetic acid and sodium carbonate were employed for the adjustment of pH at such specified levels .

2.2.2.2 /11 Presellce o/Mordalll

Dyeing of si lk and wool fabrics with pomegranate solution ( 1 0% owf) was also carried out in the presence of different specified mordants following three different methods, e.g. pre-mordanting, post­mordanting and simultaneous mordanting; 5g/L mordant concentration was employed in all the cases. In the pre-mordanting method, the fabrics were first immersed in an aqueous solution of mordants for 45 min at 70°C and then rinsed thoroughly with disti l led water. The mordanted fabrics were then dyed at 90°C for 1 h with the material-to- l iquor ratio of I :50. For simultaneous mordanting, the fabrics were immersed in a bath containing mordant and dye solution. The dyeing temperature was kept at 90°C and dyeing was carried out for I h with the material-to-liquor ratio of I :50. In case of post-mordanting, the dyeing was carried out in the absence of mordants at 90°C for 1 h and a cold wash was given thereafter. Dyed fabrics were then mordanted in a separate bath at 70°C for 45 min. Soaping of all the dyed fabric samples was done employing 2g/L non-ionic detergent at 60°C for 1 0 min. Finally, the fabric samples were cold washed and dried. Dyeing of the above substrates following pre-mordanting methods as described above was done at different speci fied dye bath pH ranging from 2 to 10 .

2.2.3 MeaslIrement of Wavelength of Maxim 11m Absorption

The wavelength of max imum absorption (Amax) of pomegranate solution at different specified pH was measured employing U-2000, UV-visible absorbance spectrophotometer of HITACHI, Japan, after di luting the solution to an appropriate level .

2.2.4 Estimation of Exhallstion of Pomegranate Sollltion

The exhaustion of pomegranate solution 7 to different specified substrates was estimated from the difference of initial concentration of pomegranate solution taken in the dye bath and final concentration remained in the dye bath ( including that of wash liquor) after exhaustion . The d ifference was expressed as percentage of in i tial concentration i n each case. The concentration of colouring component was estimated fol lowi ng a standard method7

colorimetrically employing U-2000, UV-visible absorbance spectrophotometer of HITACHI .

2.2.5 Measuremellt of KlS Vallie

The K/S values of different dyed samples were measured using Macbeth 2020+ reflectance spectrophotometer and ColourLab+ software i nterfaced with a computer. For the above purpose, the measurement of reflectance was done at Amax under 065 i lluminant. The reflectance values (R) of the dyed fabric at Amax were converted to the corresponding K/S values using the Kubelka-Munk equation [K/S = ( l _R)2/(2R)] , where K is the absorption coefficient; and S, the scattering coefficient. 8 The result shown here is the average of seven scans over a wavelength range of 400-700 nm for each sample.

2.2.6 Asse.wllellt of Colollr Fastlless Properties

Light fastness was assessed i n accordance with IS : 2454 - 1 984 on an MBTF (Mercury Bulb Tungsten Filament) light fastness tester. Colour fastness to washing was assessed as per IS : 336 1 - 1 984 (ISO-II) in a launderometer.

3 Results and Discussion

3. 1 Wavelength of Maximum Absorption

Table I shows the wavelength of maximum absorption and observed colour of aqueous solution of pomegranate in the absence and presence of acid, alkali and mordanting agents. In the absence of any agent, aqueous solution of pomegranate gives a pH value of 4.3 with a yel low-brown colour, showing its wavelength of maximum absorption at 397nm. With

Table 1 - Wavelength of maximum absorption of pomegranate solution

Pomegranate solution pH A.m •. x. Colour treated with nm observed

None 4.3 397 Yellow brown

Hydrochloric acid - 2 .0 390 Yel low

Sodium carbonate 6.0 4 1 5 Yellow brown (darker)

Sodium carbonate 8.0 445 Red brown Sodium hydroxide - 1 1 .0 45 1 Red brown

Magnesium sulphate 3 .7 395 Yellow brown

Aluminium sulphate 2 .5 Complete Yellow precipi tation of the lake

Ferrous sulphate 2. 3 Col loidal l ake Dark grey formed

DAS et (Ii. : DYEING OF WOOL AND SILK WITH PUN1CA GRANATUM 561

i ncreasing pH of the aqueous solution (Table 1 ), a bathochromatic shifting i n wavelength of maximum absorption towards h igher wavelength i s observed giving a Amax of 45 I nm at the pH of 1 1 . The colour of the aqueous solution also changes steadily from yellow-brown to red-brown i n consequent to such shifting of wavelength of max imum absorption with the i ncrease i n pH value of aqueous pomegranate solution. Among the mordanting agents used in the study, magnesium sulphate causes i nsigni fi cant shifting of Amax with no complex formation. The aqueous coloured solution of pomegranate becomes almost colourless upon addition of aluminium sulphate in consequent to immediate formation and precipitation of adsorption complex or ' lake' by the colouring component present in aqueous solution of pomegranate rind in presence of aluminium.9

Formation of such chelate with the colouring component (ellagi-tannin-flavogallol) present in pomegranate upon addition of feITous sulphate was also observed and the adsorption complex in such case was observed to remain in aqueous phase i n colloidal state without immediate precipi tation, giving a dark grey colour as was reported by other workers earlier.6 Aqueous solution of pomegranate in the presence of alumin ium sulphate shows yellow colour due to formation of complex l o with the colouring components of aqueous extract of pomegranate rind.

3.2 Effect of Varia lion in pH

The effect of variation in pH on the exhaustion of dye bath in the absence of any mordant for s i lk and wool fabrics, and acryl ic yarn and also on depth of shade (measured in terms of KIS) for wool and s i lk substrates in the absence and presence of mordants is shown in Figs 1 and 2 respectively. I t i s observed that the acryl ic fibres wi th anionic s i tes do not have any affin i ty towards pomegranate solution under all the pH range, which i s also supported by i nsigni fi cant KIS values under all the pH range (Table 2). Exhaustion of this dye to s i lk and wool, however, observed to be maximum under acidic condition and the exhaustion decreases wi th the increase in dye bath pH; under alkaline condition (PH 1 0) , i nsigni ficant dye uptake i s observed (Fig. 1 ) . The percentage exhaustion of pomegranate solution to s i lk and wool (Fig. 1 ) and KIS value of those substrates (Table 2) follow a common i ncreas ing trend with lowering of the dye bath pH. Protonation of both the fibres commonly results in an increase in dye uptake, showing maximum at dye bath pH 2. In view of the structure

shown elsewhere6, it is assumed that the dye-fibre attraction in the absence of mordants depends chiefly on ( i ) ionic attraction between electron-rich phenoxide ions of phenols, carbonyl groups of flavogallol and electron defic ient N H3 + groups of protein fibres (charge transfer force)" and ( i i ) van der waals ' i nteraction between hydrophobic part of dye anion having benzene rings and hydrophobic parts of

80

� 60 c: o 'iii 40 :::l "' .t: � 20 +---­

------.. --------------6.-o �----------------------------===-�---4 6

pH 8 1 0

Fig. I - Exhaustion of pomegranate solution on (.) acry l ic, (_ ) s i Ik and ( "' ) wool substrates against dye bath pH

(]J :::l "' >

1 0 Wool

5

1/l 0��----------�--�---------------

i: 1 0

Silk

5

:- � j. Iii =i 0

2 4 6 8 1 0

pH

Fig. 2 - KIS values against dye bath pH for wool and si lk dyed with pomegranate in presence of ( 0) MgS04, ( "' ) AI2(S04)" (L'1) FeS04 as Illordanting agents and (_) no Illordanting agent

Table 2 - Effect of variation in pH on KIS value for si lk. wool and acry l ic dyed with pomegranate

Substrate KlS (A. = 420 nm) pH 2 pH 4 pH 6 pH 8 pH t o Substrate

Wool 4.06 3.5 1 2.56 2.07 1 .63 0.59 Si lk 1 .56 1 .54 1 . 1 7 0.87 0.57 0.30

Acryl ic 0.36 0.26 0.25 0.26 0.20 0.07

562 INDIAN J . FIBRE TEXT. RES . . DECEMBER 2006

protein fibres adjacent to the amino groups. The affin i ty of dye at near neutral pH is due to the presence of benzenoid rings in the colouring component of pomegranate that i mparts affin ity for wool and si lk to thi s dye. Keratin in wool and hydrocarbon chain of s i lk fibre hav ing hydrophobic regions lead to such hydrophobic dye-fibre i nteraction in near neutral pH in a s imi lar manner as observed for the application of acid dye on protein fibres. 1 2. J 3

However, i n view of reported significant hydrolytic degradation of protei n fibres at pH :::; 2.5 under elevated temperature of dyeing for a prolong t ime l 2 ; the appreciable dye uptake at pH 4 for both the fibres as observed is of practical s ignificance. Dye uptake as assessed in terms of percentage exhaustion and KIS value of the dyed fabric appears to be higher i n case of wool than that observed in case of s i lk for all the pH used in this study. Thi s may be due to the presence of more amino groups and h igher amorphous regions of wool fibre as compared to those of s i lk . 1 2 . u

It is observed from Fig. 2 that among the mordanting agents chosen for this study, the abi l i ty of mordanti ng agents for promoting colouration of both wool and si lk commonly follow the order: ferrous sulphate > aluminium sulphate > magnesium sulphate.

3.3 Effect of Variation in Mordanting Methods

Application of aqueous solution of pomegranate on wool and s i lk substrates employing magnesium sulphate, aluminium sulphate and ferrous sulphate as mordanting agents following pre-, post- and simultaneous mordanting methods has been reported. The results of such studies assessed in terms of KIS, L, a and b are shown i n Table 3 . For pre- and post­mordanting methods, the abi l ity of the mordant ing

agents to i ncorporate the colouring component present in pomegranate in the structure of wool and si lk follows a common order: ferrous sulphate > aluminium sulphate > magnesium sulphate, as evident from the KIS values of the respective dyed substrates. However, for s imultaneous mordanting method, the abi l i ty of the mordanting agents to transfer the dye follows a common order: magnesium sulphate > ferrous sulphate > aluminium sulphate for both the substrates mentioned above. This fact may be viewed as the consequence of relati ve abi l ity of metal ions to form complex with the colouring component. Iron ancl aluminium (with their superior complex forming abi l i ty) form complex more readi ly in aqueous phase prior to transportation of colouring matter on to the substrate than does magnesium, thus giving poor KIS value of the dyed substrates for s imultaneous mordanting. Magnesium sulphate in the dye bath for s imultaneous mordanting promotes exhaustion of the dye on to the substrates as an electrolyte. For pre- or post- mordanting method, however, the superior complex forming abi l i ty of alumin ium and ferrous 1o

could be realised in the fibre, as evident from the KIS value of the respective samples (Table 3) . Effect of variation in mordanting methods using three different mordanting agents, as described above, on the s i lk substrates i s found to be s imi lar to that for wool substrates (Table 3) .

3.4 Colour Fastness t o Light and Washing

Table 4 shows data for colour fastness to l ight ancl washing for wool and si lk, when dyed with and without mordanting agents at pH 4. The rating for colour fastness to washing for both the above substrates appears to be 4 for change in colour and

Table 3 - Effect of mordanting mcthod on colour valuc

Fibre Mordanting Prc-mordanti ng Post- mordanting Simultancous mordanting agent KIS L a b KIS L {/ b KIS L a b

(A. = 420 nm) (A. = 420 nm) (A. = 420 nm)

Si lk Magnesium 1 .89 86.0 0.99 1 2.53 1 .69 85.37 1 .34 1 2. 1 8 2 .79 85.75 1 . 1 5 1 2.78 sulphate Aluminiulll 3.93 9 1 .59 -2.45 1 7.40 2.56 88.59 -0.6 1 1 4. 1 3 2. 1 1 90.28 - 1 .37 I n.6S sulphate Ferrous 5.4 1 77.49 0.56 2.28 4. 1 6 77.23 0.26 2.27 2.58 76. 1 5 0.86 1 .24 sulphate

Wool Magncsium 3 .77 8 1 .58 1 .82 1 5 .5 3.75 80.78 2. 1 4 1 5 .44 5. 1 7 8 1 .3 1 1 .74 1 5 .74 sulphate Aluminium 4.75 85.25 -0.63 20.33 4.48 83.80 -3.70 1 7 .0 2.39 84.32 -0.94 1 9.4 1 sulphate Ferrous 1 2.3 68.26 0.89 1 .93 9.52 69.0 - .074 0.86 3. 1 9 67.6 0.6 1 0.65 sulEhate

DAS et (/1. : DYEING OF WOOL AND SILK WITH PUNICA GRANATUM 563

Table 4-Colour fastness to l ight and washing for si lk and wool dyed with pomegranate

Substrate

Si lk

Wool

Dye bath pH

4

4

Type of mordant

Ni l Alumin ium sulphate Magnesium sulphate Ferrous sulphate Alumin ium sulphate Magnesium sulphate Ferrous sulphate Alumin ium sulphate Magnesium sulphate Ferroussulphate

Ni l Alumin ium sulphate Magnesium sulphate Ferrous sulphate Alumin ium sulphate Magnesium sulphate Ferrous sulphate Alumin ium sulphate Magnesium sulphate Ferrous sulphate

Mordanting method

Post- mordanting Post- mordanting Post- mordanting Pre- mordanting Pre- mordanting Pre- mordanting Simultaneous mordanting Simultaneous mordant ing Simultaneous mordanting

Post- mordanting Post- mordanting Post- mordant ing Pre- mordanting Pre- mordanting Pre- mordanting Simultaneous mordanting Simultaneous mordanting S imul taneous mordanting

1 00 95 00 85 130

c: 0 75 .� � 70 � � 1 00 :l 0 "0 95 u *

00 85 130 75 70

Light fastness

3 4-5 3-4 4 5 3-4 4 3-4 3-4 3-4

3-4 5 4 4-5 5 4 4 3-4 3-4 3-4

• •

Change in colour

3-4 4

3-4 3-4 4

3-4 3-4 4 4

3-4

4 4 4 4

3-4 4 4 4 4 4

•

Wash fastness Stai n ing on cotton

4 4 4 4 4 4 4 4 4 4

4 4 4 4 4 4 4 4 4 4

•

:

Stain ing on s i lk

3-4 3-4 3-4 3

3-4 4 3

3-4 4 3

3-4 4 4 4

3-4 3-4 3-4 3-4 3-4 3-4

Wool •

--e

�

Silk • ----------------.------11

�.----...-- .. '--�._k_�-___ ...___ ___ .& .--------.----....-_----..-----....

2 3 4 5 Number of wash cydes

3-4 for staIn Ing on adjacent fabrics, commonly i n absence and presence of three mordanting agents used. Different mordanting methods (pre, post and simultaneous) appear to have no effect on the colour fastness to washing of s i lk and wool fabrics dyed with the pomegranate solution for al l the three mordanting agents used. Such h igh colour fastness to washing even in the absence of any mordant i s the consequence of presence of ionic attraction and non­polar van der waals ' i nteraction between colouring component of pomegranate and protei n fibres as stated earli er. Colour fastness to l ight for wool and silk dyed with this dye in the absence of any mordanting agent was i mproved commonly by > 1 point upon application of aluminium sulphate and ferrous sulphate as the mordanting agents for two different mordanting methods (pre and post); s imultaneous mordanting method, however, appears to be i ncapable of causi ng such i mprovements i n colour fastness to l ight of dyed substrates (Table 4) . Fig. 3 - Colour retention against wash cycle for wool and si lk

3.5 Effect of Progressive Wash

Colour retention of dyed wool and s i lk (expressed in terms of percentage KIS of respective unwashed samples), retained for different wash cycles (up to 5 , ISO-II) , i s shown i n F ig . 3 . The retention of colour of the dyed substrates for the use of three mordanting agents follows the order: aluminium sulphate >

dyed with pomegranate i n presence of ( . ) MgS04• ( . ) AI2(S04h, (e) FeS04 a s mordanting agents and ( + ) no mordunting agent

ferrous sulphate > magnesium sulphate > no mordant. H ighest dye retention for use of aluminium sulphate as the mordanting agent may be viewed as the consequence of already reported higher chelating

564 INDIAN J. FIBRE TEXT. RES. , DECEMBER 2006

abi l i ty of aluminium than that of ferrous i n consequent to higher charge of the former metal ion. 14

4 Conclusions Dyeing of s i lk and wool with pomegranate solution

i s found to be effectively accompl i shed at pH 4.0. Aluminium sulphate and ferrous sulphate, when used as mordanting agents, fol lowing a common pre­mordanting method i mprove colour uptake, l ight fastness and colour retention of dyed substrates. Use of such mordants, however, produces no i mprovement in wash fastness of dyed substrates. Colour fastness to l ight and washing of s i lk and wool dyed w i th this dye in the absence of mordant at pH 4.0 appears to be around 3-4 and 4 respectively. Mordanting with aluminium sulphate, magnesium sulphate and ferrous sulphate do not show any posit ive influence on wash fastness properties, but the l ight fastness rating has been improved by 1 - 1 .5 points when aluminium and ferrous sulphate were used as mordanting agents. The use of ferrous sulphate and aluminium sulphate as the mordanting agents alter the tone of dyed substrates towards grey and yellow respecti vel y, whereas the use of magnesium sulphate as mordanting agent produces no significant tonal change as compared to un­mordanted dyed substrates.

References I Bose T K, Mitra S K & Sanyal 0, Fruits: Tropical {{lid

SlIbtropical, 3Td edn, Vol II (Naya Udyog, Kolkata), 2002. 1 27.

2 Singh A, Fruit Physiology alld Producti{)/z, 4Th edn (Kalyani Publ ishers, New Delhi). 1 997, 432-435.

3 EI-Nemr S E, Ismail I A & Ragab M, Nahnlllg. 34 ( 1 990) 60 1 -606.

4 Ansari A A & Thakur B 0, Colollrage, 47(7) (2000) 1 5-20. 5 Bhattacharyya N & Vairagi S, Colourage. 49(4) (2002) 47. 6 Gulrajani M L, Gupta 0 B, Agarwal V & Jain M. Inriiall Text

J, 1 02( 1 0) ( 1 992) 78 - 83. 7 Das 0, Samanta A K & Dasgupta P C, I1zriimz J Fibre Text

Res, 22( I ) ( 1 997) 53-60. S Bi l lmeyer F W & Saltzman M, Principles 0/ Color

Techllology, 2nd edn (A Wil ley I nterscience Publication ). 1 98 1 , 1 40.

9 Vogel A I. Textbook o{ Macro {{lid Semi Micro Qllalitative IlIorg({lzic Allalysis, revised by G Selah (Oriental Longman, New Delhi) , 1 985, 250-253.

1 0 Lee J 0 , COllcise Illorgallic Chemistry, 5Th edn (Blackwell Science Ltd . ), 1 996, 389 653.

I I Johnson A , The Theory (�{ Coloratioll 0/ Textiles, 2n� edn (Society of Dyers and Colorists), 1 989, I I I .

1 2 Bird C L, Theory alld Practice of Wool Dyeillg. 4Th edn (Society of Dyers and Colorists), 1 982, 9 38.

1 3 Gulrajani M L, Chell/ical Processillg (�f Silk ( Indian I nstitule of Technology. New Delhi). 1 993. 1 06- 1 1 4.

1 4 Glasstone S , Text Book of Physical Chell/istry, 2nd edn (The Macmi l lan Press Ltd, London), 1 996. 1 243- 1 244.