36

Fibre Chemistry, Vol. 49, No. 1, May, 2017 (Russian Original No. 1, January-February, 2017)

MATERIALS SCIENCE

ANTIBACTERIAL CHARACTERISTICS OF CELLULOSE

MATERIALS MODIFIED WITH COPPER NANOPARTICLES

B. R. Tausarova and Zh. E. Shaikhova UDC 677.027.62

Methods for the synthesis of copper nanoparticles by reduction of copper sulfate in an aqueous mediumin the presence of polyvinylpyrrolidone are examined. The effect of the content of the employed reagents,the pH of the medium, and the temperature on the synthesis of copper nanoparticles was investigated.The antibacterial characteristics of cellulose materials modified with copper nanoparticles aredescribed.

Investigation of the nanoparticles of metals has a significant role in the development of modern nanotechnologies[1-3]. This is due primarily to the broad spectrum of possibilities for their practical application, in which use is made both of thecopper nanoparticles themselves and of materials modified by them. Under present-day conditions investigations are beingactively developed on methods of modifying cellulose fibers in order to create a wide assortment of novel high-grade materialswith biocidal characteristics. One way of solving this task is to produce materials containing nanoparticles (NPs) of copper.

Copper nanoparticles have high activity toward all biological subjects starting from viral particles and endingwith the human organism and can be used for ecological and medicinal purposes. The number of papers on study of theantiviral and antibacterial activity of copper NPs, which increases from year to year, bears witness to the increasedinterest of researchers in this problem from both the fundamental and the practical standpoints [4-11]. Textile materialswith antimicrobial characteristics are used for the manufacture of clothing, linen, dressings, and sanitary equipment andare effective as protective means against infections.

The aim of the present work was to develop cellulose materials with antimicrobial properties acquired as aresult of treatment with solutions based on copper nanoparticles. The subjects for investigation were purely cotton fabricof group Art. 94-533 manufactured by Almaty Cotton Plant, and the chemicals were copper sulfate, polyvinylpyrrolidone,and potassium hypophosphite.

Copper sulfate is inorganic compound (a copper salt of sulfuric acid), nonvolatile, odorless, very hygroscopic,and readily soluble in water. It has disinfectant, antiseptic, and astringent properties. It is used in medicine and in plantcultivation as an antiseptic, fungicide, or copper–sulfur fertilizer.

Polyvinylpyrrolidone (PVP) is a polymer white or yellowish in color and soluble in water and other polarsolvents. Its density is 1.2 g/cm3, and its melting point is 150-180°C.

Potassium hypophosphite forms colorless crystals, is soluble in water, and has a molecular mass of 104.99 g/moleand a density of 2.0 g/cm3.

The copper nanoparticles were synthesized by reduction of an aqueous solution of copper sulfate by the followingprocedure. To 5 ml of the aqueous solution of copper sulfate (C = 1-3 M) we added an equal volume of PVP. We thenadded 5 ml of a solution of potassium hypophosphite (C = 1-3 M) and made the solution alkaline to pH 9-11 withammonia solution. The reduction was carried out at 40, 60, and 80°C. After heating for 5 min the solution had a brownishcolor indicating the formation of copper nanoparticles.

Almaty Technological University, Republic of Kazakhstan. Translated from Khimicheskie Volokna, No. 1, pp.38-41, January-February, 2017. E-mail: birtausarova@mail.ru

0015-0541/17/4901-0038© 2017 Springer Science+Business Media New York

DOI 10.1007/s10692-017-9837-3

37

After determination of the exact weight on an analytical balance samples of cotton fabric measuring 200×200mm were impregnated with aqueous solutions of the polymeric compositions on a laboratory two-roll padder with 90%wringing. Needle frames in a drying cabinet with a thermal regulator were used for drying and heat treatment. Afterdrying and heat treatment the sample was washed in distilled water and was then dried at room temperature.

The microscopic investigations were done with a scanning electron microscope on a JSM-6510LA instrument.

a b c

d

Fig. 1. Photographs of copper nanoparticles obtained with a scanningelectron microscope with CuSO

4 contents 1·10-2 (a), 2·10-2 (b), 4·10-2

(c), and 6·10-2 M.

a b c

d

Fig. 2. Photographs of the surface of fibers treated with coppersulfate solution with concentrations 1·10-2 (a), 2·10-2 (b), 4·10-2

(c), and 6·10-2 M.

38

The biocidal properties of the cotton fabric were checked by the Koch method, by means of which it is possibleto determine the microbial contamination of samples of dressed cotton fabrics.

During the synthesis of copper nanoparticles by reduction of copper sulfate in aqueous solution sodiumhypophosphite was used as reducing agent. The general equation of the reaction looks as follows:

CuSO4 + 2KH

2PO

2 + 6H

2O = Cu + 5H

2↑+ K

2SO

4 + 2H

3PO

4

In order to determine the optimum content of the initial components a series of experiments in several stageswere carried out (Table 1).

In order to establish the stability of the sols with time the obtained hydrosols were studied by spectrophotometryin the region of wavelengths between 400 and 800 nm [12]. The structure and size of the product depend to a large degreeon the reaction conditions and on the copper sulfate content. Copper nanoparticles of various sizes can be obtained by

Fig. 3. The amounts of mesophilic aerobic and, not necessarily, anaerobic microorganisms detected in sampleswith various contents of CuSO

4 in the solution (M): 1) 0 (control); 2) 1·10-2; 3) 2·10-2; 4) 4·10-2; 5) 10-2.

1 2 3 4 5

Table 2. Results of Microbiological Analysis*

Sample No. Microbiological parameters AMANAnM, CFU/g g/cm3 1 contro l Confluent gro wth (6000)

2 109

3 98

4 86

5 72 6 10

_______________ *GOST 10444.15-94

Table 1. Contents of Initial Components

Sample No. Contents of components, M

PVP CuSO4 KH2PO2

1 0.01 0.02 0.02 2 0.02 0.02 0.02 3 0.05 0.02 0.02 4 0.06 0.02 0.02 5 0.02 0.05 0.01 6 0.02 0.01 0.03 7 0.02 0.03 0.04 8 0.02 0.04 0.05 9 0.02 0.06 0.06

39

increasing the reaction time. The following optimum conditions for the synthesis of copper nanoparticles were obtained:pH 9-10, content of copper ions 0.04 M, PVP 0.02 M, potassium hypophosphite 0.04 M.

As shown by the investigations (Fig. 1), the obtained nanoparticles have various forms with diameters between1 and 100 nm and are present as both fine and coarse particles, i.e., the particle sizes range from nanometers to micrometers.In many cases the fine particles form accumulations or agglomerates. The particles are stable, are not deposited, and donot change color.

The investigations on the scanning electron microscope (Fig. 2a, b) confirmed that the structure of the materialcontains nanosized particles in the form of individual clusters of copper NPs. As the copper content on the surface of thetreated fabric increases the amount of adsorbed nanoparticles increases (Fig. 2b), while the particles are distributednonuniformly on the surface.

The antimicrobial characteristics of the fabric were assessed from the degree of inhibition of bacterial growthafter various incubation times in comparison with control samples of the same fabric without nanoparticles. Themicrobiological parameters AMANAnM (amount of mesophilic aerobic and, not necessarily, anaerobic microorganisms)are presented in Table 2.

As seen from the data presented in Table 2, 1 g of sample 2 contained 0.109·103, sample 3 0.098·103, sample 40.086·103, and sample 5 0.072·103 CFUs (colony-forming units), while bacterial growth was not observed in sample 6.Significant bacterial growth was observed in the control sample (untreated cotton fabric): its surface (25 cm3) containedmore than 6000 cells.

It is seen from Figs. 3 and 4 that mesophilic aerobic and, not necessarily, anaerobic microorganisms(Staphylococcus aureus) multiply successfully on the control fabric sample 1. However, their number decreases in thesamples of fabrics treated with copper nanoparticles. The antibacterial characteristics of the samples are increased if thecontent of copper nanoparticles is raised.

REFERENCES

1. A. Yu. Olenin, Uspekhi Khimii, 80, No. 7, 635-662 (2011). 2. G. E. Krichevskii, Nanochemical, Biochemical, and Chemical Technologies in the Production of New Generation

of Fibers, Fabrics, and Clothing [in Russian], Uch. Posobie, Moscow (2011), 507 pp. 3. B. R. Tausarova, A. Zh. Kutzhanova, et al., Vestnik Almatinskogo Tekhnologich. Un-ta, No. 1 (102), 76-83

(2014). 4. Humberto Palza, Int. J. Mol. Sci., 16, 2099-2116 (2015). 5. A. Burkitbai, B. R. Tausareva, et al., Izv. Vuzov. Tekhnol. Tekst. Prom-sti, No. 3 (357), 67-70 (2015). 6. A. Burkitbay, B. R. Taussarova, et al., Fibers & Textiles in Eastern Europe, 22, No. 2 (104), 96-101 (2014). 7. Hossam E. Emam, Avinash P. Manian, et al., Surface & Coatings Technology, No. 254, 344-351 (2014). 8. Mary Grace, M., Navin Chand, Sunil Kumar Bajpai, J. Eng. Fibers a. Fabrics, 4, 24-35 (2009). 9. M. N. K. Chowdhury, M. D. H. Beg, et al., Coll. Polymer Sci., 293, 777-786 (2015).10. A. M. Mikhailidi, N. E. Kotel’nikova, et al., Izv. Vuzov. Tekhnol. Leg. Prom-sti, 3, No. 1, 61-65 (2009).11. S. M. Rakhimova, A. Vig, et al., Text. Ind. Technol., No. 3 (357), 202-205 (2015).12. Zh. E. Shaikhova, B. R. Tausarova, A. K. Kozybaev, Khim. Zhurn. Kazakhstana, Almati, No. 2 (50), 175-179 (2015).

Fig. 4. Growth of AMANAnM — total microbe number on fabric samples: 1) control sample; 2-5) samplestreated with solutions with copper nanoparticle contents of 1·10-2, 2·10-2, 4·10-2, and 6·10-2 M respectively.

1 2 3 4 5