Nanoparticles of zeolite in surface modification of textile materials.

Markovic, Lea ; Tarbuk, Anita ; Grancaric, Ana Marija 等

Abstract: The new textile applications for achieving the materials for human performance (medical, protective and sports) is one of nine themes according the European Technology Platform for the Future of Textiles. The present paper is an attempt to modify cotton and polyester fabric surface with addition of natural zeolite nanoparticles for achieving UV protective textile material. Zeolite in this paper refers to activated particles of clinoptilolite, with high fraction of nanoparticles (80%), produced by tribomechanical processing in the patented machine. The capability of UV protection of the cotton and polyester fabrics after modification, zeolite and FWA treatment was determined according to AS/NZS 4399:1996 using transmission spectrophotometer Cary 50 (Varian). The impact of zeolite on fabric whiteness was discussed as well.

Key words: zeolite, cotton, polyester, UV protection

1. INTRODUCTION

Materials for human performance, such are medical, protective and sports, is one of nine themes according to the European Technology Platform for the Future of Textiles. Textile and clothing is a human's second skin, therefore it is the most suitable interface between environment and human body. It is ideal tool for personal protection and safety (Jayaraman et al., 2006).

A good fabric UV protection is a guaranty that clothing will have the ability to protect the skin from incident solar energy. In addition to some beneficial effects of UV radiation (UV-R, from 100 nm to 400 nm) on skin it may cause skin damage such as sunburn, allergies, skin aging and even skin cancer especially during the summer time. The UV-C radiation (from 100 nm to 280 nm) get absorbed by atmosphere, but UV-B (from 280 nm to 320 nm) and UV-A (from 320 nm to 400 nm) rays reach the Earth and cause known skin aging and recently the formation of skin malignant neoplasm. Diminishing of the ozone layer raised this risk, what have resulted with large investigation of fabric UV protection (Reinert G. et al. 1997, Grancaric et al. 2006). It is well known that garment provides some UV protection. Fabric can reflect, absorb and scatter solar wavelengths, but in the most cases it does not provide full sun screening properties. UV protection highly depends on a large number of factors, such are type of fiber, porosity, density, moisture content, type and conc. of dye, UV-B protective agents, and fluorescence whitening agents (FWA) in the case of white textiles, if applied (Algaba I., Riva A., Crews P.C. 2004). Natural zeolites are crystalline aluminosilicates with unique adsorption, cationexchange, and catalytic properties.

[FIGURE 1 OMITTED]

It has multiple uses in industry and agriculture. According to Ivkovic, S et al. (2004) zeolits have also been investigated in a broad spectrum of medical uses; such are tumor and diabetes mellitus. Due to its cationexchange ability zeolites were used in water purification and in detergents for longer time period. Megamin[R] is a natural zeolite clinoptilolite with enhanced physicochemical properties. It has a cage-like structure (Fig. 1) consisting of high portion of SiO2 (60-67%). It was produced by tribomechanical processing in the patented machine. When applied externally in powder form, it has also been found to quicken the healing of wounds and surgical incisions. It is proven bactericides and fungicides as well (Ivkovic, S. 2004). In recent studies, applied to textile material it scatters the light, resulting in UV protection (Grancaric A.M., Tarbuk, A., Sadikovic M. 2006).

In this paper sun screening properties of cotton (C) and polyester (poly(ethylene-terephtalate), PET) fabric after standard surface modifications--cotton mercerization and PET alkaline hydrolysis; and after treatment with zeolite nanoparticles and FWA's were investigated.

2. EXPERIMENTAL

2.1 Material

In this paper nanoparticles of zeolite (Z) were applied to cotton and polyester fabric before and after surface modification for achieving better UV protection. Cotton fabric used was a plain weave fabric of 100% cotton yarn of 20 tex and surface mass 125 g/[m.sup.2]. Fabric was chemically bleached in peroxide baths (CB) and mercerized (CBM) in a bath containing 24% NaOH, 8 g/l anionic surfactant Subitol MLF (Bezema) in a liquor ratio 1:25, 2 min, at 18[degrees]C, than rinsed and neutralized. 5 g/l of zeolite nanoparticles were applied to bleached (CBZ) and mercerized (CBMZ) cotton fabric by impregnation and dryed on 100[degrees]C for 2 min. Uvitex BHT (Ciba), FWA--three stilben derivate was applied in optimal concentration of 6 g/l in process similar for zeolite.

Polyester fabric (PET) used was poly(ethylene-terephtalate) previously heat set, having surface mass of 100 g/[m.sup.2]; textured multifilament yarns in both warp and weft. Alkaline hydrolysis (PETH) was performed in 1,5 mol/l NaOH with 2 g/l cationic surfactant Lyogen BPN (Sandoz) as an accelerator by batch wise method for 10 min at 100[degrees]C, in stainless-steel bowls (Linitest, Original-Hanau), than rinsed and neutralized. 5 g/l of zeolite nanoparticles were dispergated in bath containing 0,5 g/l CHT dispergator (Bezema) and applied to untreated (PETZ) and hydrolized (PETHZ) polyester fabric by thermosol process. Fabric was dryed at 80[degrees]C for 2 min following by setting at 200[degrees]C for 30 s. Uvitex ERN-P (Ciba), FWA--benzoxazole derivate was applied in optimal concentration of 6 g/l in similar thermosol process as zeolite.

2.2 Methods

Remission spectrophotometer SF 600 PLUS CT (Datacolor) was used for measuring CIE whiteness and Yellowing Index according to DIN 6167 Description of yellowing of practically white or practically colorless materials. UV protection was determined through Ultraviolet protection factor (UPF) using transmission spectrophotometer Cary 50 Solarscreen (Varian) according AS/NZS 4399:1996 Sun Protective Clothing: evaluation and classification.

3. RESULTS AND DISSCUSSION

This paper investigates the application of nanoparticles of zeolite on cotton and polyester fabric after well known surface modifications--cotton mercerization and PET alkaline hydrolysis. The influence of this application to fabric UV protection, whiteness and yellowness were determined after treatment with zeolite nanoparticles and FWA's. Results of UV protection expressed through mean UPF values are shown on Fig. 2.

UPF indicates how much longer the person can stay in the sun with the fabric covering the skin as compared with the uncovered skin to obtain same erythemal response. Fig. 2. indicates that polyester fabric give off better UV protection than cotton fabric after surface modification and treatment with nanoparticles of zeolite due to polyester chemical constitution. Polyester fiber has double bonds in polymer chain which can absorb small amounts of UV-R. Nevertheless, small amounts of UV-R are reflected from polyester multifilament. After FWA treatment it is evident that cotton fabric absorbs higher amounts of FWA. Bleached cotton is non-rateable for UV protection. Mercerization, as standard cotton modification, results in higher cotton absorbility and little increment of UPF, because fabric shrinks. Nanoparticles of zeolite on fabric surface scatter UV-R resulting in better UV protection. Additionally, zeolite increase fabric surface area resulting in higher adsorption of FWA. Therefore, mercerized and zeolite treated cotton fabrics give off excellent UV protection after FWA. UPF values for polyester fabric show similar behavior as for cotton fabric. Modification of polyester fabric results in little better UV protection, while treatment with nanoparticles of zeolite results in good UV protection. FWA treatment of polyester results in good protection as well. Meanwhile, FWA treatment to polyester fabric with zeolite results in very good UV protection.

[FIGURE 2 OMITTED]

Spectral characteristics of cotton and polyester fabrics were measured using spectrophotometer Datacolor SF 600 PLUS CT. CIE whiteness and yellowness index were calculated automatically. Results are collected in Table 2.

It is evident that high effects in textile cleaning of genetic and added impurities such are waxes, protein substances, pectin and other during scouring leads to cotton whitening. Bleaching in peroxide baths removes pigments resulting in white cotton. Natural zeolites are yellowish, therefore small lost of fabric whiteness and small yellowing occurs. Optical brightening results in great increment of cotton fabric CIE whiteness because fabric is hydrophilic and absorbs high amounts of FWA. Even zeolites are yellowish, active surface area is higher, what leads to high CIE whiteness. Polyester fabric adsorbs only small amounts of optical brightener. Therefore, fabric whiteness slightly increases. Analogue to whiteness increment, yellowing index decreases.

4. CONCLUSION

Surface modification of textile materials--cotton mercerization and alkaline polyester hydrolysis slightly increase fabric UV protection. Nanoparticles of zeolite applied to fabric surface result in good UV protection. FWA treatment leads to excellent UV protection for cotton and very good protection for polyester. Even though natural zeolites are yellowish do not affect fabric whiteness significantly. It is to point out that nanoparticles of zeolite and FWA give off synergistic effect in fabric UV protection.

5. REFERENCES

Algaba I., Riva A. and Crews P. C. (2004). Influence of Fiber Type and Fabric Porosity on the UPF of Summer Fabrics, AATCC Review, Vol. 4, No. 2, 26-31, ISSN 1532-8813

Grancaric, A.M. et al. (2006). UV Protection of Pretreated Cotton--Influence of FWA?s Fluorescence, AATCC Review, Vol. 6, No. 4; 40-46, ISSN 1532-8813

Grancaric, A.M., Tarbuk, A., Sadikovic, M. Nanoparticles of Zeolite in the Future Textile Finishing, Proceedings of Futurotextiles Conference, Koncar et al. (Eds.), 147-153, ISBN, Lille, Nov 2006, ENSAIT, Roubaix

Ivkovic, S. et al. (2004). Dietary Supplementation with the Tribomechanically Activated Zeolite Clinoptilolite in Immunodeficiency: Effects on the Immune System, Advan. in Therapy, Vol. 21, No. 2, 135-147, ISSN 0741-238X

Jayaraman, S.; Kiekens, P.; Grancaric, A.M. (2006), Preface, In: Intelligent Textiles for Personal Protection and Safety, Jayaraman, S.; Kiekens, P.; Grancaric, A.M. (Eds.), I, IOS Press, ISBN 1-58603-599-1, Amsterdam

Reinert G. et al. (1997). UV Protecting Properties of Textile Fabrics and their Improvement, Textile Chemists and Colorists, Vol. 29, No. 12, 36-43, ISSN 0040-490X

MARKOVIC, L[ea]; TARBUK, A[nita] & GRANCARIC, A[na] M[arija] *

Table 1. Fabric labels and treatments

Label Treatment

CB Bleached cotton fabric
CBM Bleached mercerized cotton fabric
CBZ Bleached cotton fabric impregnated with zeolite
CBMZ Bleached mercerized cotton fabric impregnated with zeolite
PET Untreated polyester fabric
PETH Hydrolized polyester fabric
PETZ Polyester fabric impregnated with zeolite
PETHZ Hydrolized polyester fabric impregnated with zeolite

Table 2. CIE whiteness ([W.sub.CIE]) and yellowness index (YI) of
cotton and polyester fabrics after surface modification and treatment
with nanoparticles of zeolite and FWA

 After treatment Treatment with FWA

Fabric [W.sub.CIE] YI [W.sub.CIE] YI

CB 75,7 3,4 121,1 -12,5
CBM 72,9 3,9 123,2 -11,7
CBZ 68,6 5,5 122,2 -12,0
CBMZ 67,2 6,4 124,2 -10,9
PET 66,9 6,5 85,8 2,0
PETH 67,3 6,4 81,7 -0,4
PETZ 66,8 6,5 83,3 1,1
PETHZ 64,9 7,1 84,7 0,2