Chitosan pretreatment for cotton dyeing with black tea

J Campos, P Díaz-García, I Montava, M Bonet-Aracil and E Bou-Belda

Universitat Politècnica de València, Departamento de Ingeniería Textil y Papelera, Pl.

Ferrándiz y Carbonell s/n, 03801, Alcoy, Spain

Email: evbobel@txp.upv.es

Abstract: Chitosan is used in a wide range of applications due to its intrinsic properties.

Chitosan is a biopolymer obtained from chitin and among their most important aspects

highlights its bonding with cotton and its antibacterial properties. In this study two different

molecular weight chitosan are used in the dyeing process of cotton with black tea to evaluate

its influence. In order to evaluate the effect of the pretreatment with chitosan, DSC and

reflection spectrophotometer analysis are performed. The curing temperature is evaluated by

the DSC analysis of cotton fabric treated with 15 g/L of chitosan, whilst the enhancement of

the dyeing is evaluated by the colorimetric coordinates and the K/S value obtained

spectrophotometrically. This study shows the extent of improvement of the pretreatment with

chitosan in dyeing with natural products as black tea.

1. Introduction

Chitosan is an N-deacetylated derivative biopolymer of chitin (2-acetamido-2-deoxy-β-D-glucose

through a β (1-4) linkage). The deacetylation of chitin is never completed and there is no specified

nomenclature that describes the degree of deacetylation [1, 2]. Chitin can be easily acquired from crab

or shrimp shells. Its N-deacetylation is performed under alkali environment as shown in figure 1. The

chitin that has been formed from the shells is deacetylated in 40% sodium hydroxide at 120°C for 1-

3h. This produces 70% deacetylated chitosan. Most natural polysaccharides are neutral or acidic, but

chitin and chitosan are highly basic polysaccharides [3]. The bond between chitosan and cotton is a

difficult bond because of the likeness of the two polymers and it has to be dissolved in an acid to

improve the bond. This is only possible as result of the highly basic nature of chitosan.

Figure 1. N-deacetylation of chitin to chitosan

The bonding of chitosan with cotton happens after the cotton is oxidised [4]. Figure 2 shows how

the cotton (I) is oxidized (II) and its reaction place with chitosan (III).

Figure 2. Oxizidation of cotton (a) and reaction with chitosan (b) [4]

Chitosan has a wide range of applications. It is most known for its use in wound dressing [5, 6] but

it has however a lot of other uses. It can be used in photography, cosmetics, as artificial skin, as

contact lens, heavy metal capturing in polluted water, colour removal in textile mills, paper finishing,

drug delivery system, etc. But is most important feather might be the fact that is an antibacterial agent

[7].

2. Objective

The main objective of this work is to study the influence of the chitosan molecular weight and its

concentration in dyeing with black tea and the curing temperature of the cotton treated with two

different molecular mass chitosan, low and medium.

As the curing is necessary for a good bond between cotton and chitosan, the cotton gets dried at 60 ºC

and cured at different temperatures.

3. Materials and methods

In the present paper, we used chitosan as a natural mordent. One has low molecular weight (XL), and

the other one medium molecular weight (XM). Both types of chitosan were commercial products,

supplied by Sigma-Aldrich. Different kinds of concentration were used, 5 g/L and 15 g/L of both types

of chitosan. As a natural dye, black tea was used by boiling it in water for 2 hours using 2 g/L of

concentration.

The fabric used was a cotton twill fabric with 210 g/m2 which had been chemically bleached in an

industrial process. After the chitosan treatments, cotton samples were dryed at 80°C in a screen

printing engineering TD-20. After drying, treated samples were cured at different temperatures: 80,

140 and 200°C in a WTC Binder 030.

Dyeing experiments were performed using M:L (material to liquor) ratio of 1:40 with manual

agitation using 50% dye concentration. Dye baths temperatures were raised to 90-95ºC for 1 h.

The influence of curing temperature was performed on a DSC with the aim of determining the change

in behaviour of the chitosan after treatment on cotton. The test was performed on a Metler Toledo

DSC 1 Stare System with Stare software by heating 20°C/min and a range from 30°C to 400°C. In

order to evaluate and compare objectively the influence of pre-treatment of cotton with chitosan, the

dyed samples were analyzed in a reflection spectrophotometer MINOLTA S.A CM-3600d model with

standard 10º observer and illuminant D65, whereby the chromatic coordinates in the CIELAB space

and the colour strength (K/S) were obtained according to the Kubelka-Munk equation.

4. Results and discussion

First of all, the DSC results obtained, show the difference between two chitosan’s molecular weight.

There is a common peak around 100°C caused by the loss of water. while the peak at 320°C gives the

temperature of decomposition of amine (GlcN) units with correspondent exothermic peak at 295 °C

[8].

Figure 3: DSC of the low and medium chitosan molecular weight

In figure 4, 5 and 6 the results of DSC analyses of the cotton fabric treated with both types of

chitosan and untreated fabric are shown. The concentration of chitosan used is 15g/L in order to

maximize the effect of the chitosan on the cotton surface fabric. Figure 4 shows the results of treated

and dried fabrics using chitosan low and medium.

Figure 4. DSC of untreated fabric and cotton treated chitosan 15g/L and cured at 80 degrees

The thermogram found, reported in Figure 4, is quite comparable to those related to cotton

material, reported in literatura. The DSC curve of the untreated and treated fabrics show the same

thermal behaviour, seeing the loss of water at 90 ºC and a endothermic curve at 380 ºC approximatly,

due to the cellulose depolymerization [9].

As can be seen in figure 5 and 6 samples dryed at 80ºC and cured at 140 and 200ºC, respetively show

the same endothermic curve, not being able to observe any significant difference.

Figure 5. DSC of untreated fabric and treated fabric with 15g/L of chitosan and cured at 140 degrees

Figure 6. DSC of cotton treated chitosan 15g/L and cured at 200 degrees

Unfortunately the exothermic peak related to the decomposition of amine (GlcN) units of chitosan,

which is observed in figure 3, disappears analysing treated fabrics, being completely hidden by the

substrates decomposition peaks, so quantitative considerations cannot be done. In a second step, the

effect of using low chitosan or medium chitosan as a mordant in the dyeing process was studied in

more details in terms of color strength, quantified by calculating the staining level K/S values from

reflectance measurements on the dyed fabrics. The K/S results show that pre-treated cotton with

chitosan as a mordant has more colour strength than untreated cotton dyed, so this suggests that the

treatment with chitosan enhances the linkage between the black tea dye and the cellulose.

Furthermore, there is a significant difference between the K/S values of the fabric pretreated with

chitosan low and medium, being this value higher when medium chitosan is used as mordant.

Figure 7. K/S diagram for black tea dyeing with XM and XL pretreated cotton

5. Conclusions

In this work the influence of pre-treatment with chitosan in natural dyeing has been verified using

black tea as a natural dye. It has been tested in an exhaustion dyeing bath and the results show that

fabrics pre-treated with a natural mordant have better colour strength than fabrics which have not been

pre-treated. The medium molecular weight chitosan shows better K/S value than the dyeing with pre-

treated cotton with low molecular weight chitosan.

On the other hand, it hasn’t been possible to study the curing temperature of pre-treatment by DSC

results because there is no difference after comparing the results of each treated sample with the

untreated fabric results.

As result it is possible to say that a concentration of 5g/L of chitosan medium is enough to get good

dyeing results with natural dyes, without damaging the cotton fabric. However, the use of different

experimental techniques to know the optimum curing temperature is necessary.

References

[1] Muzzarelli, R. A. 1973 Natural chelating polymers; alginic acid, chitin and chitosan Natural

chelating polymers; alginic acid, chitin and chitosan, Pergamon Press.

[2] Zikakis, J. 2012 Chitin, chitosan, and related enzymes. Elsevier.

[3] Kumar, M. N. R. 2000 A review of chitin and chitosan applications. React Funct Polym, 46(1),

pp 1-27

[4] Gupta, D., and Haile, A. 2007 Multifunctional properties of cotton fabric treated with chitosan

and carboxymethyl chitosan. Carbohydr Polym, 69(1), pp. 164-171

[5] Montazer, M. and Afjeh, M. G. 2007 Simultaneous X-linking and antimicrobial finishing of

cotton fabric. J. Appl. Polym. Sci, 103(1), pp 178-185

[6] Rinaudo, M. 2006 Chitin and chitosan: Properties and applications. Prog Polym Sci, 31(7), pp

603-632

[7] Shirvan, A. R., Nejad, N. H. and Bashari, A. 2014 Antibacterial Finishing of Cotton Fabric via

the Chitosan/TPP Self-Assembled Nano Layers. Fiber Polym, 15(9), pp 1908-1914

[8] Kittur, F. S., Prashanth, K. H., Sankar, K. U. and Tharanathan, R. N. 2002 Characterization of

chitin, chitosan and their carboxymethyl derivatives by differential scanning calorimetry.

Carbohydr polym, 49(2), pp 185-193.

[9] Lessan, F., Montazer, M. and Moghadam, M. B. 2011 A novel durable flame-retardant cotton

fabric using sodium hypophosphite, nano TiO2 and maleic acid. Thermochimica Acta,

520(1), pp 48-54

0

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K/S

Wavelengh (nm)

CO-210

BLACK TEA XM

BLACK TEA XL

Bio-functionalization of conductive textile materials with redox

enzymes

M Kahoush 1,2,3,4

, N Behary 1, 2

, A Cayla 1, 2

and V Nierstrasz 3

1 Ecole Nationale Supérieure des Arts et Industries Textiles (ENSAIT), GEMTEX

Laboratory, 2 allée Louise et Victor Champier BP 30329, 59056 Roubaix, France 2 Université de Lille, Nord de France, France 3 Textile Materials Technology, Department of Textile Technology, The Swedish School

of Textiles, Faculty of Textiles, Engineering and Business, University of Borås, SE-501

90, Borås, Sweden 4 College of Textile and Clothing Engineering, Soochow University, Suzhou, China

Email: may.kahoush@ensait.fr

Abstract. In recent years, immobilization of oxidoreductase enzymes on electrically conductive

materials has played an important role in the development of sustainable bio-technologies.

Immobilization process allows the re-use of these bio-catalysts in their final applications.

In this study, different methods of immobilizing redox enzymes on conductive textile materials

were used to produce bio-functionalized electrodes. These electrodes can be used for bio-processes

and bio-sensing in eco-designed applications in domains such as medicine and pollution control.

However, the main challenge facing the stability and durability of these electrodes is the

maintenance of the enzymatic activity after the immobilization. Hence, preventing the enzyme’s

denaturation and leaching is a critical factor for the success of the immobilization processes.

1. Introduction

Immobilization of oxidoreductases or redox enzymes (EC1) on conductive fibres and textiles is a method

that can be used to produce small size flexible equipment for various applications replacing expensive,

rigid, and big size materials. It can be used to fabricate electrodes for biosensors and biofuel cells used in

many fields like medicine, environment, and energy production. These enzymes have been immobilized

using different techniques like, covalent bonding, cross linking, adsorption, and mechanical compression

for confinement into conductive support (1–4). A variety of conductive materials have been used to

fabricate these electrodes (anode or cathode) like, multi-wall carbon nanotubes (MWCNT) and poly (3, 4-

ethylenedioxythiophene (PEDOT) combination, platinum black, gold coated porous silicon with

nanotubes, carbon fibers, graphite and gold (1,2,5–8).

This study focuses on the bio-functionalizing of textile based on a conductive nonwoven carbon felt by

immobilizing glucose oxidase redox enzyme to produce electrodes which may be used for different

applications such as biofuel cells and biosensors.

2. Materials and methods

The materials used were as follows: carbon felt from CeraMaterials. The conductive polymer poly (3, 4-

ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) obtained from HERAEUS. Glucose oxidase

G 7141 EC (1.1.3.4) and D-glucose were obtained from Sigma-Aldrich. The glucose oxidase activity kit

was purchased from Megazyme.

3. Enzyme immobilization

Commercial carbon felt (5*5 cm2)(non-treated or PEDOT:PSS dip-coated) was placed in enzyme solution

1mg.ml-1 concentration (138.4 U.ml-1) at pH 5.5 and temperature of 4°C for 24 hours, then washed twice

with a buffer solution, and stored at 4°C until use.

The obtained bio-functionalized felts can be used as electrodes because of the enzyme’s ability of

catalyzing oxidation reaction of D-glucose, which releases electrons as shown in equation (1).

C6H12O6 + H2O + O2 C6H12O7 + 2e- + 2 H+ + O2 (1)

4. Results and discussion

The results ‘Figure 1’ show that at pH 7 and 25°C, electrodes obtained from physical adsorption on the

carbon felt coated with PEDOT:PSS gave better enzymatic activity than the non-treated carbon felt for the

first cycle of enzymatic activity essay using glucose oxidase activity kit. Furthermore, the samples with

PEDOT: PSS coating maintained better activity when performing a second cycle using the same kit and

same conditions. This refers to good affinity of PEDOT:PSS with the enzymes due to its composition of a

mixture of cation/anion ionomers

Figure 1. Enzymatic activity for glucose oxidase at pH 7 and 25 °C for non-treated carbon felt and

PEDOT: PSS coated carbon felt samples.

Electrical behavior of the obtained electrodes showed to depend on glucose concentration and the scan

rates used during the cyclic voltammetry tests. Regarding the substrate used, when the glucose

0

0,02

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0,08

0,1

0,12

Enzy

mat

ic a

ctiv

ity

U.c

m-2

NTCF

PEDOT :PSS coated CF

First cycle second cycle

Gox

concentration increases, more substrate will have direct access to the active sites of the immobilized

enzymes, and consequently higher electrical currents are obtained. However, when all the active sites of

the immobilized enzymes are occupied for a certain moment, the increased substrate concentration does

not result in any augmentation of the obtained electrical current. Furthermore, the current obtained showed

to be dependent on the scan rate used in the cyclic voltammetry. Indeed, at slow scan rates, the flux

towards the electrode is small compared to the faster rates because of the diffusion layer, which results

according to Randles-Sevcik in smaller currents recorded.

5. Conclusion

Immobilization of the enzyme glucose oxidase on conductive carbon felt was achieved using two

methods. Immobilization by adsorption on the carbon felt coated with PEDOT:PSS yielded a better

enzymatic activity and reusability. These obtained electrodes aim to be used in sustainable applications

related to energy and pollution control.

Acknowledgments

This project is financially supported by Sustainable Management and Design for Textiles (SMDTex)

Erasmus Mundus joint Doctorate Program (n°2015-1594/001-001-EMJD).

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[8] Mano N, Mao F and Heller A 2004 A miniature membrane-less biofuel cell operating at +0.60 V

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