Dyeing of Bio-Treated Cotton / Wool Blend Fabric with New Natural Dye. H.S.El-khateeb*

Transcription

1 Dyeing of Bio-Treated Cotton / Wool Blend Fabric with New Natural Dye H.S.El-khateeb* Textile Printing, Dyeing &Finishing Dept.,Faculty of Applied Arts,Helwan University,Giza,Egypt. Abstract : One- bath dyeing of cotton/wool knitted blend was carried out using new natural dye which was extracted from the bark of camphor tree (Eucalyptus citriodora ) after biotreatment process by using brewer's yeast suspension which contain many enzymes. Factors that may affect the enzymatic treatment process were studied and various parameters that may affect the dyeing process were investigated such as dye conc., ph, temp. and time and addition of salt.wettability and color strength were measured, also different fastness properties were assessed after post mordanting process. Key words: Knitted cotton /wool blend Brewer's yeast suspension Camphor tree - Dyeing Wettability -Mordanting -Fastness properties. Introduction: Textile manufacturers and consumers generally recognize wool/cotton textiles as superior products that combine the rich full hand of wool with the comfort of cotton.(1) It is a comfortable, durable and attractive fabric. The complementary properties of these fibers include wool s high elongation and weakness at low stress and cotton s resistance to elongation and strength at high stress. Wool s low thermal conductivity and hygroscopicity, leading to apparent dryness, complement cotton s propensity to dissipate heat and absorb moisture with easy wettability. While cotton maintains high thermal conductivity, wool retains low thermal conductivity up to moisture regains of about 15% () Dyeing a cotton/wool blend is difficult because the two fibers have different chemical makeup. Wool, which is sheep hair, is made of animal proteins, while cotton is made of plant cellulose the main part of a plant s cell wall. Normally, when wool and cotton are blended together, two separate dye baths are required because the wool takes up most of the dye. Wool is dyed in an acidic environment at high temperatures, and cotton is dyed in a non- acidic environment at lower temperatures. This difference requires that the wool and cotton be dyed either separately, or sequentially in one bath in which the ph and temperature levels are changed.( 3, ) Anywhere, many researches and development in finishing and dyeing of cotton/wool blend have been undertaken in recent years. (5-1) * ohala1@yahoo.com 1

2 Historical records of the use of natural dyes extracted from vegetables, fruits, flowers, certain insects and fish dating back to 35 BC have been found. Color is the main attraction of any fabric. However, due to the toxic nature and adverse effect of synthetic dyes, The natural dyes are experiencing renewed interest because of the importance of green and natural products. Nowadays we witness a growing interest in their application in the fields of textiles, (11,1,13) food and paints. Natural dyes produce very uncommon sootting and soft shades as compared to synthetic dyes. For successful commercial use of natural dyes, the dyeing techniques need to be adopted without scarifying required quality of dyed textile materials. Therefor, to obtain newer shades with acceptable colour fastness, appropriate procedure need to be derived from scientific studies on dyeing methods, dyeing kinetics and compatibility of selective natural dyes. (1) However, many attempts have been carried out to elucidate the fundamental aspects of natural dyes as well as to enhance their fastness properties, especially washing and light fastness, by using several metallic mordants taking in consideration the ecological aspects. (15) Enzymes can be used in order to develop environmentally friendly alternative processes. (1) In the last ten years, the textile industry has become one of the main field of industrial applications of enzymes. Different enzymes are commonly used in various stages of textile processing. (17). Most of the enzymes used are derived from fungal sources such as Amylase (Aspergillus niger), Protease (Aspergillus oryzae) and Lipase (A. niger). (1) The aim of this work mainly focused on dyeing cotton/wool knitted blend with new natural dyes ( camphor plant ) in one bath after enzymatic preatreatment by using brewer's yeast suspension which contain many enzymes such as (protease,lipase,amylase) in order to improve better dye uptake on the two fiber cotton and wool. - Experimental:.1- Materials :.1.1- Fabric: Cotton/wool blended knitted fabric : ( 5 / 35 ) were kindly supplied by Misr/ Helwan for Spinning and Weaving Co., Cairo, Egypt..1.-Dyestuff: Natural dye from vegetable source was extracted from the bark of camphor tree ( Eucalyptus citriodora ) Enzymes : The suspension of active brewer's yeast {(fung) saccharomyces uvarum and saccharomyces cerevisiae }was used in the present work. Yeast was obtained from the Egyptian Starch, Yeast and Detergents Campany, Egypt Chemicals and auxiliaries: Sodium carbonate, acetic acid, Alum ( Aluminum Sulfate), Ferrous sulfate, sodium chloride, were used in the present work.

3 .- Methods:..1- Preparation of Enzyme Suspension: The suspension of active yeast fungus was prepared by pasting the brewer's by adding such amount of sugar (1g of sugar to 1 g of dry basis) then water was added to the paste of yeast while well stirring to complete the total volume to one litre. Finally the solution was filtrated and freezed...- Preparation of plant material: The plant materials were dried in dry air at 35 o C for hours till the plant become after which they were grinded..-3-extraction of Natural Dyes: crisp The plant materials were soaked in water for hours, using 1 g of plant materials in 1 ml water and then the colouring matter was extracted at the boil for 3 minutes after which the solution was filtered and stored under refrigerator..-- Pretreatment of Cotton/wool blended fabrics: Cotton/wool blended knitted fabrics were treated by using the filtrated brewer's yeast suspension after diluted it with water to obtain aqueous suspension of different conc. ( 5-1%). the treatment was carried out at ph values from (5-9) for times ( 15-75) and temperature from ( - o C ). After that the blended fabrics were rinsed with cold and hot water. Then the enzymatic pretreated blended fabrics were soaped with g/l non-ionic detergent at 7 o C for 15 min. and rinsed after washing with cold water..-5- Dyeing of Cotton/Wool blended fabrics with natural dye: The pretreated cotton/wool blended knitted fabrics were dyed in one-bath by using the extract of the bark of camphor tree with different conc. (5-1 % ) at ph from ( 5-) for ( 3-9 min. ) and the temperature were ( -1 o C ) at L:R Mordanting process: The post- mordanting process was carried out after the optimum dyeing on cotton/wool blended fabrics by using 5 g/l of different mordants (Alum, Ferrous, copper ). the process was continued for min. at boiling, after which the samples were soaped with g/l non- ionic detergent for 15 min at7 o C..3-Measurements and testing:.3.1- Colour measurements: The dyed samples were subjected to colour measurement by using reflection spectrophotometer model ICS-Texicon Limited, Kennetside Park, New Burg, Berkshire, England. The colour strength expressed as K/S values was assessed by applying the Kubelka Munk equation: K/S= (1- R) /R Where K and S are the absorption and scattering coefficient respectively, and R is the reflectance of the dyed fabric..3.- Colour fastness: Fastness properties of dyed samples were tested according to ISO standard methods. The specific tests were: ISO-X1(197), colour fastness to rubbing; ISO 15-C (199), colour fastness to washing; and ISO 15-E, colour fastness to perspiration. The dyed samples were subjected to tests, for fastness to light by AATCC test method

4 K / S.3.- Determination of wettability: The wettability of cotton/wool blended fabric can be observed by determining the rate of absorption of blended fabric to water after the enzymatic treatment. This test was carried out by putting two drops of water on the knitted fabric surface and calculate the time that will be passed until the fabric absorb the water. 3- Results and Discussion: The present work was focused on two points, first the enzymatic pre-treatment of cotton/wool blended knitted fabrics with brewer's yeast which contain many enzymes i.e.( amylase, lipase,protease) that improved the dyeability of two fiber towards camphor natural dye, second point one bath, one step process is used for dyeing the blend to obtain solid shade Factors affect the enzymatic treatment of cotton/wool knitted blended fabrics: Effect of Brewer's Yeast Suspension Conc. : Raw cotton/wool knitted fabrics were pretreated by using brewer's yeast suspension at different conc. ( ml/l) under fixed conditions of time, temp, and ph. After enzymatic treatment, dyeing process with camphor plant was carried out. The colour strengths of the dyed knitted blend were measurd and the results are plotted in fig. (1) without 5 cm 5 cm 75 cm 1 cm Brewer's yeast suspenstion conc.(ml/l) Fig.(1):Effect of enzyme concentration of the bio-treatment on the colour strength (K/S) of dyed cotton/wool blend. Bio-treatment condition: X enzymes conc.,ph,min.,temp. o c 5% camphor extract,ph 7, min,temp.1 o c

5 K /S It can be noticed from figure (1) that increasing the enzymes conc. was accompanied with an appreciable increase in K/S of cotton/wool knitted fabric until reaches its maximum value at the higher conc. of enzymes. this result is an expected one, since the rate and magnitude of hydrolytic reaction between enzyme and the impurities depends on great extent on enzyme concentration. (19) The enzymes that found in the brewer's yeast (protease, amylase, lipase ) ( ) increasing dye up take on the two fabric. The action of enzymes consists of increasing dye absorption and also seems to produce a better diffusion of the dye into the fabric. (17) In the case of wool, wool mainly consists of proteins and lipids. Various enzymatic methods have been used to modify the properties of wool including application of proteases, lipases, protein disulphide isomerase and transglutaminase. Proteases can be used in order to reduce felting shrinkage of wool by hydrolyzing the cuticle cells of the fibers and thereby reducing the inter-fiber friction. (,1). The surface of the wool fiber is hydrophobic due to the presence of lipid. Wool fiber should become very hydrophilic after lipid removal. The lipase enzymes have been used in to remove lipids from the outer layer of the wool fiber.(,3) And in the case of cotton, cotton has several impurities such as fats and waxes which impart poor water absorbency. Amylase is applied in desizing process and presence of lipase should improve not only desizing but also the scouring process. Also lipase enzyme degrade waxy materials and used with amylase to degrade lipids.(19) 3.1. Effect ph of Enzymatic treatment : The stability of an enzyme and the catalytic activity are related to the ph value of the solution. It is important to control ph to suit enzyme, in order to get the most efficient enzyme performance. Cotton/wool knitted blend were subjected to enzymatic treatment at different ph values while the other conditions were constant. the result are illustrated in fig. which indicates the influence of ph of pretreatment on the dyeability of two fiber in blend ph 5 ph ph 7 ph ph 9 ph valu of pretreatment Fig.():Effect of ph of pretreatment on the colour strength (K/S) of dyed cotton/wool blend. 1% enzymes conc.,phx,min.,temp. o c 5% camphor extract,ph 7, min,temp.1 o c 5

6 K / S It is clearly shown from figure that maximum K/S is achieved at ph. The activity of the enzyme is greatly related to stability of its three- dimensional structure and the availability of the active-sites for binding with substrate will thus, be influenced with their number and degree of ionization. Enzyme has an optimum ph, and its activity decrease sharply on both sides of the optimum range. Extremes of ph alter the ionization of the active-sites and cause great disturbance of the enzyme protein. Thus enzyme loses its natural structure and hence its activity. () 3.1. Effect of Enzymatic treatment temp. : The activity of enzyme is very sensitive to temperature of the reaction medium, so it is important to determine the most suitable pretreatment temperature. Cotton/wool knitted blend were bio-treatment at various degrees of temperature and then dyed. The results show in figure C C 7 C C Pre-treatment temp. ( o C) Fig.(3):Effect of pretreatment temp. on the colour strength (K/S) of dyed cotton/wool blend. 1% enzymes conc.,phx,min.,temp.x 5% camphor extract,ph 7, min,temp.1 o c Fig. 3 illustrates that raising the temperature of the treatment is accompanied with increasing of K/S, the maximum value was obtained at o C and this result means that at o C the activity of the applied enzyme suspension reach its maximum. This result shows that maximum catalytic activity of enzymes in brewer's yeast suspension as well as higher efficiency of removing the impurities from two fibers surface in the blend may be realized at o C and the dyeability will be enhanced at this temperature Effect of Enzymatic treatment time : The pretreatment with brewer's yeast suspension was carried out at o C by using a constant conc. of enzymes at ph for different durations ( min.) after which the knitted blend was dyed. The results are found in fig. which illustrate the relation between time of treatment and attained color strength.

7 K / S It is evident from the figure that the higher color strength was obtained after minutes, after which the K/S was decreased and this means that increasing of the time of pretreatment minimized the reactivity of the enzymes min min 9 min 1 min 1 min Pretreatment time Fig.():Effect of pretreatment time on the colour strength (K/S) of dyed cotton/wool blend. 1% enzymes conc.,phx,xmin.,temp. O C 5% camphor extract,ph 7, min,temp.1 o c 3.1. Wettability of cotton/wool knitted blend : The wettability reflect the degree of water absorption of the fiber, so the wettability test was carried out to indicate the relation between the enzymatic pretreatment and the rate of water absorption by the fiber. Table (1) illustrates the alteration in the wettability as a function of enzymatic treatment using different concentrations of brewer's yeast suspension. Conc. of brewer's yeast suspension (%) zero Time of disappearance of water drop on cotton/wool knitted blend min. sec. sec. 3 sec. 1 sec. These results show that the wettability of cotton/wool knitted blend increases gradually as the conc. of the used enzymes increase which may be attributed to the modification of morphological structure of two fiber. Hydrophobicity (water repellence) of textiles is frequently associated with self-cleaning properties. When a water droplet rolls off the surface, the surface impurities such as dust get carried away by the droplet resulting in a self-cleaning effect.(5) Enzyme treatments effectively remove non-cellulosic substances. This results in a hydrophilic surface and improved wettability.() 7

8 K / S 3.- Factors affect dyeing of cotton/wool knitted blended with camphor plant: This investigation was focused on using new natural dye which extracted from the bark of camphor tree for dyeing cotton/wool knitted blend after enzymatic treatment. Camphor tree (Eucalyptus citriodora) belongs to Lauraceae family. This large, round-canopied, evergreen tree has broad, large-diameter, unusually strong branches and can reach 7 feet in height with a broader spread but is usually to 5 feet with a to -foot spread. The stems and bark on young branches of Camphor-Tree are bright green, tinged with red when young, maturing into a dark grey-brown.() The major parts of natural dyes are anthraquinone, anthocyanin and flavonoid dyes or polyphenolic compounds, most of which have yellow, red, brown, and olive shades.(7) The main color of dye extracted from camphor bark was brown Effect of dye concentration: The pretreated cotton/wool knitted blend were dyed by using extract of camphor plant with different concentrations ( 5,5,75,1 %) under fixed dyeing condition. The results obtained are observed in fig.(5) % 5% 75% 1% Champor extract conc. Fig.(5):Effect of champor extraction conc. on the colour strength (K/S) of pretreated cotton/wool blend. 1% enzymes conc.,phx,xmin.,temp. O C x % camphor extract,ph 7, min,temp.1 o c It is clear that the color strength increases as the concentration of camphor dye extract increase. This result due to the enzymatic treatment which actually improve the dye uptake on the two since its dyeability is improved and the rate of dye diffusion inside the fiber is accelerated to attain higher color strength. Lipases are used with amylase enzyme to assist the removal of lubricants present in size and enhance absorbency of cotton fiber for better dyeing. (19) Also the fatty layer which decrease the affinity of natural dyes to wool fiber can be removed by using enzymatic treatment.

9 K / S 3..Effect of ph values: The physico-chemical properties of the dyeing process depend on the ph value especially in ionic dyeing system. The relation between the uptake of natural dye on cotton/wool knitted blend was studied and the results are plotted in fig ph 5 ph ph 7 ph ph 9 ph of dyeing Fig.():Effect of ph of dyeing bath on the colour strength (K/S) of pretreated cotton/wool blend. 1% enzymes conc.,phx,xmin.,temp. O C 1 % camphor extract,ph X, min,temp.1 o c It is clearly noticed from the figure that the maximum dye exhaustion was observed to attain at ph 7. This result indicates the behavior of this new natural dye with the variation of ph of dyeing process on knitted blend.the effect of dye bath s ph can be attributed to the correlation between dye structure and two fibers in the blend. Cotton fiber act high percentage (5%) in the blend, so it play the important role in the dyeing bath with different factors. At ph 7 the attraction between the dye and the fibers increase as decrease the degree of cotton ionization, but further rise in ph made the dye and fabric more anionic which repelled each other and caused lesser dye ability on higher ph 3..3Effect of salt concentration: Neutral electrolytes such as sodium chloride and sodium sulphate play a great role in dyeing textile fibers. Pretreated knitted blend were dyed in presence different concentrations of NaCl (without,1, 3,5,7,9 ). Fig. 7 indicates the effect of the presence salt in the dyeing bath. It is clearly observed from the figure that the color strength slightly increase as the increasing of salt concentration in the dye bath and this logic one, because the salt reduced or neutralized negative charge on cotton fiber. Electrolytes may be considered as exhausting agent in case of dyeing cellulosic fiber with anionic dyes whereas it plays as leveling agent in case of dyeing wool fiber specially at low ph medium. 9

10 K / S K /S without 1g/l 3g/l 5g/l 7g/l 9g/l NaCl Salt conc. g/l Fig.(7):Effect of salt concentration in the dyeing bath on the colour strength (K/S) of pretreated cotton/wool blend. 1% enzymes conc.,phx,xmin.,temp. O C 1 % camphor extract,ph 7,salt x, min,temp.1 o c 3...Effect of dyeing temp. : The results of the K/S which illustrate the relation between dyeing temp. and the color strength of the dyed cotton/wool knitted blend are indicated in fig C C C 1 C Dyeing temperature o C Fig.():Effect of dyeing temperature on the colour strength (K/S) of pretreated cotton/wool blend. 1% enzymes conc.,phx,xmin.,temp. O C 1 % camphor extract,ph 7,salt x, min,temp.x The results shows that the rate of dyeing for the dye used, increases as the temp. increase and the rate of increasing the K/S of dyed blend. As it is observed, the percentage of dye bath exhaustion increased with the increase of dyeing temperature. This efficiency can be attributed to the higher kinetic energy of the dye molecules and their consequent greater migration power towards the fibers. In addition, a higher extent of fiber swelling would contribute to the increased dye exhaustion as temperature was raised. (7) 1

11 K / S 3..5.Effect of dyeing time : Effect of dyeing time was studied and the results obtained are illustrated in fig min 3 min 5 min min 75 min Dyeing time Samples dyed cotton/wool knitted blend Post Modanted sample with alum Post Mordanted sample with ferric sulphate Post Modanted sample with copper Fig.(9):Effect of dyeing time on the colour strength (K/S) of pretreated cotton/wool blend. 1% enzymes conc.,phx,xmin.,temp. O C 1 % camphor extract,ph 7,5g/lsalt, x min,temp.1 o C It was seemed that the color strength gradually increased as the time increase. This can be attributed to the slight diffusion with short dyeing time. Because coloring component attained equilibrium from dye bath to fabric, which increases with time. 3.- Fastness properties : The color fastness is usually rated by loss of depth of color in original sample. The results of fastness properties of dyed cotton/wool knitted blend by using camphor plant after post-mordanting with different mordants (alum,ferric,copper ) are cited in table (). Table :Colour fastness properties of cotton/wool knitted blended fabrics dyed with camphor plant Washing Perspiration Light Alt. Staining Acid Alkali Alt. Staining Alt. Staining * ** * ** * ** * staining on cotton **staining on wool 11

12 It can be concluded that fastness properties were good to excellent specialy after postmordanting with mordants. The chemistry of binding of natural dyes to fibers is complex. It involves direct bonding, H- bond and hydrophobic interactions.mordants help binding of dyes to fabric by forming a chemical bridge from dye to fiber, thus decreasing the staining ability of a dye along with increasing its fastness properties. Mordant form insoluble compounds of the dye within the fiber. The presence of certain functional groups in suitable positions in the dye molecule causes its coordination to the metal ion. () -Conclution: Cotton/wool knitted blend was dyed with new natural dye (camphor plant) in onebath, after successful bio-treatment by using brewer's yeast suspension which contain three enzymes (lipase, amylase, protease ). The wettability was improved by applied enzymatic treatment, thus the rate of diffusion the camphor dye increased into two fiber. Using brewer's yeast suspension minimize pollution at the same time improve the dyeability of both cellulose and protein fibres in the blend fabric.also natural dye which was extracted from the bark of the camphor tree was the new one and it was the first time of using it. Fastness properties gave results ranged from good to excellent Table (3) : The colored samples of cotton/wool knitted blend dyed with camphor plant and fixed with different mordants Different Mordant Colored sample Champor plant Champor plant with Alum Champor plant with copper Champor plant with ferric 1

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