Colouration of Silk with Natural Dyes Dr. Rajashree Phukon, Registration ID- AB/565 , Assist. Prof. , Sibsagar Girls’ College, P. O. Sivasagar, Assam, Pin-785640, e-mail ID:[email protected] com and Mr Diganta Kr. Borah, Research Scholar, Department of Economics, Dibrugarh University, Assam, India, e-mail ID: [email protected] in. ABSTRACT The study was undertaken with an aim to develop the dyeing conditions of four different natural dyes which are easily available in North East India, namely Myrica nagi Thumb. (Bay berry), Garcinia xanthochymus Hook. f. Cochin goroka), Artocarpus integrifolia Linn. f. (Jack fruit), and Eugenia jambolana Lam. (Black plum) on silk yarn. The natural mordant used in the research work is Aluminium Potassium Sulphate (AlK (SO4)2) for better fixation of the dyes. The dyes are extracted by alkaline method and the extraction time is optimized from the optical density values. The pre-mordanting method is used for mordanting the yarn. Shades of different colours, ranging from yellow to brown are obtained from the dyes on silk yarn. Fastness grades rated for all the samples are found to be good irrespective of all the dyes.

The dyes are found to be an ideal source which could be adopted at commercial level. 1. Introduction Natural dyes have been part of man’s life, since time immemorial. The age-old art of dyeing with natural dyes was common in India. Natural dyes are obtained from natural sources such as vegetable matter, minerals and insects. Early efforts of colouring fabrics were hampered by the fact that some of the dyes are not very colourfast. Eventually scientist found that this defect could be partially overcome by the use of mordant.

The natural colouring substances are now developing trends for their use all over the world because of health hazards and toxicity problems created by the synthetic dyes [1]. 2. Objective: Considering the growing importance of natural colorants all over the world, the present work was undertaken with an aim to study the dyeing conditions of selected natural dyes on silk yarn. 3. Materials and methods: 3. 1 Selection and Preparation of yarn for dyeing Mulberry silk yarn was selected for dyeing and collected from a private firm near Guwahati, India.

The natural gum sericin present in the silk hinders the dyeing process and hence silk needs to be degummed. Degumming of silk was carried out by using standard method [2]. 3. 2 Selection of natural dyes: Table 1. Dye yielding plants selected for the study are: |Sl. No. |Botanical name |Common name |Family |Parts used | |1 |Myrica nagi Thumb | Bay berry |Myriaceae |Bark | |2 |Garcinia xanthochymus Hook. . |Cochin goroka |Guttiferae |Bark | |3 |Artocarpus integrifolia Linn. f. |Jack fruit |Moraceae |Root | |4 |Eugenia jambolana Lam. |Black plum |Myriaceae |Bark | 3. 3. Selection of mordant: Mordant form the link between dyestuff and fibre, which allows the dye with no affinity for the fibre to be fixed [3]. Among the mordant used for fixing natural dyes, metallic mordents are most common.

The mordant used in the research work is Aluminium potassium sulphate (alum) AlK2 (SO4)2 which is consider as eco friendly [4]. 3. 4. Selection of mordant concentration The amount of mordents used in dyeing plays an important role as the mordents forms the link between the dyestuff and fibre. After much preliminary work, the mordant concentration was determined which was mainly based on the percentage of absorption of the dye and visual assessment of the shade. Three mordant percentages were used and the observations were made at three levels i. e. 5, 10 and 15% concentrations. 3. 5. Mordanting method

Pre-mordanting method was used for this study. In this method, the yarns were mordanted in the first stage and then dyed. First optical density of the extracted dye liquor was recorded. 5, 10, and 15% solution of alum were prepared by dissolving in water. Yarn samples were then treated in each of the mordant solutions and then dyed in the prepared dye bath for various time periods for each dye. Optical density of the dye liquor was recorded before and after dyeing. Samples were then washed, rinsed and dried in shade. 3. 6. Extraction of dyes Selected natural dyes were extracted by alkaline method.

In this method, 1% of alkaline solution was prepared by adding 1 ml of Na2CO3 in 100 ml of soft water. The dye material was boiled at 80-90°C in the dye bath. Then the dye solution was filtered. The optical density of the solution was recorded 3. 7. Determination of dye absorption using spectrophotometer For determining the percentage of dye absorption by the yarn, the dye solution before and after dyeing was subjected to visual light of specific wavelength using spectrophotometer. The beam of light transmitted by the sample was detected and recorded as optical density.

The hue given by the dye was noted. To arrive at the peak wavelength suitable for the dye liquor, scanning of the dye liquor was done and the peak at which optical density was high was noted. 3. 8. Test for colour fastness All the dyed yarn samples were evaluated for colour fastness to washing sunlight, rubbing, and perspiration by the standard procedures laid down by Bureau of Indian Standards [5]. 4. Result and discussion: The findings of the present work are discussed below. 4. 1 Optimized dyeing conditions: 4. 1. 1 Optimized dye material extraction time Table 2.

Optimized dye material extraction time by determining optical density |Dye yielding plants |Extraction time, min. |Wave length (nm) |Optical density | | | | | | |M. nagi |45 |470 |0. 470 | |G. xanthochymus |45 |450 |0. 440 | |A. ntegrifolia |30 |430 |0. 411 | |E. jambolana |60 |500 |0. 324 | Table 2 revealed the optimized dye extraction time which are 45 min for M. nagi and G. xanthochymus,, likewise one hr. for E. jambolana, and 30 min for A. integrifolia based on optical density. The suitable wave length are 470. 450, 430, and 500 for M. nagi, G. xanthochymus, A. integrifolia, and E. Jambolana respectively. 4. 1. Optimized concentration for dyeing Table 3. Optimized concentration of various parameters for dyeing |Dye yielding plants |Concentration of dye |Concentration of |Concentration of the|Mordanting |Dyeing | | |material in g/100gm of |alkali g/100gm of dye |mordant g/100gm of |time(min) |time(min) | | |yarn |material |yarn | | | |M. nagi |200 |5 |10 |30 |30 | |G. anthochymus |200 |5 |10 |30 |30 | |A. integrifolia |300 |7 |15 |30 |30 | |E. jambolana |300 |10 |15 |30 |45 | The data presented on the Table 3 shows that 200gm of M. Nagi, and G. Xanthochymus each are required for dyeing of 100gm of silk where as 300gm of A. Integrifolia and E.

Jambolana each are required for dyeing of 100gm of silk. Similarly the concentration of alkali required 5gm of each for 100gm of dye material i. c. M. Nagi, G. Xanthochymus and also 7gm for A. Integrifolia and 10gm for E. Jambolana. Optimized mordanting and dyeing time are 30 mins for all the dyes except E. Jambolana where optimized dyeing time is 45mins. 5. Colour produced: The selected natural dyes produced different shades of beige, yellow and brown colours on silk yarn. 6. Fastness grades of the dyes: Table 5: Fastness grades of the dyes on silk at optimum dyeing conditions Dye yielding plants |Washing fastness |Rubbing fastness grade |Light |Perspiration fastness grade | | |grade | |fastness | | | | | |grade | | | |CC* |CS# |Dry |Wet | |Acidic |Alkaline | | | | |CC |CS |CC | | |Required |cost(`) |Required |cost(`) | | | | | |amount | |amount | | | | | |M. nagi (2kg) |100gm |15. 20 |100 |18. 00 |8. 00 |25. 00 |66. 20 | |G. xanthochymus |100gm |15. 20 |100 |18. 00 |8. 00 |25. 00 |66. 20 | |(2kg) | | | | | | | | |A. ntegrifolia |210gm |31. 92 |150 |27. 00 |8. 00 |25. 00 |91. 92 | |(3kg) | | | | | | | | |E. jambolana (3kg) |300gm |45. 60 |150 |27. 00 |8. 00 |25. 00 |105. 60 | From the Table 4, it was found that approximate cost required for dyeing 1kg of silk yarn by using optimized dyeing conditions are `66. 20 for M. Nagi, and G. Xanthochymus each where as for A. Integrifolia and E. Jambolana the calculated cost are `91. 92 and `105. 60 espectively. The cost of the dye material is not included as it is locally available. 8. Summary: From the present study, it could be concluded that the selected dyes were found to be an ideal source of natural dyes. At the 21st century, maintaining a safe environmental balance becomes even more important as synthetic dyes are based on toxic raw materials and intermediates. The effluents from the industry are some of the major causes of environmental pollution. Natural dyes are not only free from this handicap but could also assist the regeneration of the environment if plans were developed to cultivate these plant varieties on a commercial scale.

Petrochemicals, the base of synthetic dyes is limited and irreplaceable while the vegetarian based resources of dyes are replaceable besides being bio-degradable. All over the world, environmental regulations are becoming more and more stringent and are forcing a shift of technology towards less polluting or practically non-polluting areas of technological development. Keeping in view the environmental aspects, there is a need to realize the importance of exploring the technology of non-toxic natural dyes. From the present work it could be summarized that the selected natural dyes are a suitable choice for colouration of silk yarn. REFERENCES: 1. Vankar, S. P. (2001) . Current Trends in Natural Dyes for Eco friendly Textiles. Textile Indus. Trade J. 39(9-10):19 2. BIS method 15: 970-1980. 3. Singh, O. P. (2002). Natural dyes : The pros and cons. Indian Tex. J. January : 42-46 4. Gulrajani, M. L. (2001) Present Status of Natural Dyes. Indian J. Fiber Tex. Res. 26(1&2):191-201. 5. Bureau of Indian Standards No’s – IS: 3361-1979, IS : 686-1957, IS: 766-1956 and IS: 971-1956. Plate: Source of dye, part used and dyed silk yarn [pic][pic][pic] Black plum (Eugenia jambolana Lam. ) [pic][pic][pic] Jack fruit (Artocarpus integrifolia Linn. f. ) [pic][pic][pic] Cochin goroka (Garcinia xanthochymus Hook. f. ) [pic][pic][pic] Bay berry (Myrica nagi Thumb)

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