**3. Effect of electron irradiation on printability of polypropylene (PP) fabrics, (novel method for decoration of PP fabrics)**

Textile printing is the area of textile processing used for applying color in a localized design or pattern to textile material, normally fabric. Depending on the fiber composition and the construction of the fabric to be printed, as well as the proper selection of dyes or pigments, the printed patterns can exhibit good to excellent colorfastness. From a practical point of view, textile printing is the process which incorporates artistic design, engineering, and chemical technology to produce unique patterns which can then be accurately repeated on large volumes of the fabric. Textile printing is probably best described as an industrial art, having a long history and an assured future. Printing is actually local dyeing. The dye is a part of a printing paste, which is applied on the textile material by different printing techniques. After printing, it is usual to steam the textile material, to achieve colorfastness (wash, light, and rubbing fastness).

Textile print was created thanks to man's desire to decorate fabrics designated for clothing, and later for home decoration (Petrinic, Andersen, Ostar-Turk, & Le Marechal, 2007). It has logically gone through many development steps. The steps were aimed at improving the mechanization and automation of each printing technology phase. Each printing technique was created and improved step by step (Burton, 2005).

In traditional textile printing, colored images on the fabrics are produced by using textile print paste which consists of highly concentrated thickened solutions of textile dyes or pigments. Unfortunately, the use of these print pastes can lead to intensely colored waste products.

Environmental issues are of major concern to most textile printers (Moser, 2003). For many years, improving the quality of prints was the main goal in product development. Lately, economic, environmental, and toxicological considerations have become more important. Using more environmentally friendly print paste preparations and auxiliary products, for example reducing or to eliminating formaldehyde on the fabric, is currently one of the major concerns in the textile printing industry (El-Molla & Schneider, 2006).

In many cases relating to the processing of fibers, powders, and films, the modification of polymer surface functional groups composition is often required.

The development of methods for the controllable modification of polymers in order to adjust their physicochemical, mechanical, optical, and other properties without any chemical processing is one of the most important areas of polymer science and technology.

Accelerated electrons generated by an electron beam (EB) may be considered one of the most important sources of ionizing radiation in the recent years. The effects of ionizing radiation, in general, and accelerated electrons in particular range from the basic phenomena of interaction of radiation with matter, radiation physics and chemistry to industrial applications. Among the different chemical systems, polymeric materials show marked changes when subjected to the action of ionizing radiation. These changes are mainly cross-linking or degradation, which result in the formation of products with modified physical and chemical properties.

Radiation curing by EB has become a well accepted technology, which has found a large number of industrial applications mainly in the coating and printing fields, in the manufacture of adhesives, and in microelectronics (El-Naggar, Zohdy, Said, El-Din, & Noval, 2005).

Effect of Plasma on Dyeability of Fabrics 335

drying and fixating which increase the production time and costs. The results from this work show that the EB-based designing process represents a serious competitor of the conventional technologies. And just by dyeing the electron irradiated samples, the printed look appeared on the surface of PP fabrics, it is because of this matter that, PP doesn't have any affinity to cationic dyestuffs, but after EB treatment, cationic dye can be absorbed by

In order to study the chemical modification of the electron irradiated part of fabrics, Fourier transform infrared spectroscopy is used. FTIR was used to examine the functional groups of the corresponding samples investigated in Figure 8. As shown only slight increase in absorbance at 1720 cm−1 (C=O) band and 3400 cm−1 (O-H) band and 1080-1300 cm-1 (C-O) after electron irradiation can be noticed. The improvement of dye-ability properties of these uncovered parts confirmed that, electron bombardment activated successfully the surface of uncovered PP fabrics. The main effect of electron beam treatment of a polymer is the transfer of energy towards the respective polymer surface .In function of the molecular structure of the polymer, one of the following events could proceed : crosslinking , chain scission or radical stabilization. In the case of polymer treatments by Electron Beam, electrons are accelerated towards the exposed surface and lead to an increased reactivity of the respective surface. This fact is possible due to the breaking of the different bonds and further formation of free radicals. After the polymer samples are brought out from the reactor, the reaction of the oxygen from the atmosphere with the free radicals takes place, and thus surface functionalization is obtained. This

irradiated parts of fabrics easily.

Fig. 7. The Schematic view of experimental setup.

The modification of polymers is an important area of EB technologies providing an effective way to surface modification of various chemically inert materials, such as polyethylene imparting them with the reactivity required for the formation of polymer blends and grafted layers. Particularly, the high density EB treatment of polypropylene (PP) was found to promote the formation of oxygen-containing groups (mainly C=O) on the polymer surface and enhancement of PP compatibility with hydrophilic inorganic materials (El-Naggar et al., 2005; Ibrahim, Salmawi, & Ibrahim, 2005; Iller, Kukie ka, Stupi ska, & Miko ajczyk, 2002; Kondo et al., 2006; Leonhardt, Muratore, & Walton, 2004; Mahapatra, Bodas, Mandale, Gangal, & Bhoraskar, 2006; Timusa, Cincub, Bradleyc, Craciuna, & Mateescua, 2000; Vasiljeva, Mjakin, Makarov, Krasovsky, & Varlamov, 2006; Zagórski, 2004; Zsigmond, Halasz, & Czvikovszky, 2003).

I.S. Bhardwaj and his coworkers researched on the modification of PP fiber with EB. In this work, PP filaments were irradiated by different doses of EB in the presence of monomers like acrylic acid, 2-4 vinyl pyridine. The solubility, crystallinity, and tenacity of the treated fibers has been determined. There appears to be a marked improvement in the tenacity of the fiber and dye take-up (Bhardwaj & Heusinger, 1978). Also, EB treatment studies have been carried out by H.M. Abdel-Hamid to investigate the potential for improvements in the dielectric properties of the PP film (Abdel-Hamid, 2005). F. Poncin-Epaillard reported that, surface grafting of polymeric materials, such as films and fibers, may improve their surface properties and this improvement on PP active sites should initiate a surface postgrafting that can be formed by an EB irradiation. EB modified PP was also functionalized through an aging reaction, emphasized by a high radical concentration. Active surface films are susceptible to react with monomers in a postgrafting reaction (Poncin-Epaillard, Chevet, & Brosse, 1994).

In this work, the PP fabric is irradiated with electrons to form oxygen containing groups on its surface. By creating these functional groups, the uncovered part of PP fabric can be dyed by cationic dyes easily without any hazardous materials (Shahidi et al, 2007). Thus, just by dyeing the fabrics can be printed.

The aim of this research is the development of an environmental-friendly process with no thickeners in order to enable good quality printing and to minimize water pollution.

Due to low surface energy, polypropylene has very weak hydrophilic properties and doesn't have any affinity to cationic dyes. In this study, some parts of polypropylene fabrics (PP) have been covered by mask, and then they were irradiated by electrons with different energies (Figure 7). After electron irradiation, the samples have dyed with cationic dyestuff. The electron irradiated parts can be dyed and by this work we can print or decorate the polypropylene fabrics and films easily. The treated surfaces were characterized by Scanning Electron Microscopy (SEM), reflective spectroscopy and FTIR. Also, light and wash fastnesses of printed samples were measured. As we know, pigment printing method requires additional materials such as gauze, screen, screen frame, screen lake, etc. and these affect product costs. Moreover, this process requires longer times compared to Electron Beam (EB) designing. On this account EB designing is more advantageous. One of the advantages of the EB designing is the good repeatability of the designs. Besides, desired physical effects can be fully ensured. In pigment printing method printing time is lengthening and reproducibility decreases due to the difficulties such as paste preparation, squeegee motion, clogging of the screen and the necessity to print the same area for each sample. Moreover, EB designing process does not include any after-treatments such as

The modification of polymers is an important area of EB technologies providing an effective way to surface modification of various chemically inert materials, such as polyethylene imparting them with the reactivity required for the formation of polymer blends and grafted layers. Particularly, the high density EB treatment of polypropylene (PP) was found to promote the formation of oxygen-containing groups (mainly C=O) on the polymer surface and enhancement of PP compatibility with hydrophilic inorganic materials (El-Naggar et al., 2005; Ibrahim, Salmawi, & Ibrahim, 2005; Iller, Kukie ka, Stupi ska, & Miko ajczyk, 2002; Kondo et al., 2006; Leonhardt, Muratore, & Walton, 2004; Mahapatra, Bodas, Mandale, Gangal, & Bhoraskar, 2006; Timusa, Cincub, Bradleyc, Craciuna, & Mateescua, 2000; Vasiljeva, Mjakin, Makarov, Krasovsky, & Varlamov, 2006; Zagórski, 2004; Zsigmond,

I.S. Bhardwaj and his coworkers researched on the modification of PP fiber with EB. In this work, PP filaments were irradiated by different doses of EB in the presence of monomers like acrylic acid, 2-4 vinyl pyridine. The solubility, crystallinity, and tenacity of the treated fibers has been determined. There appears to be a marked improvement in the tenacity of the fiber and dye take-up (Bhardwaj & Heusinger, 1978). Also, EB treatment studies have been carried out by H.M. Abdel-Hamid to investigate the potential for improvements in the dielectric properties of the PP film (Abdel-Hamid, 2005). F. Poncin-Epaillard reported that, surface grafting of polymeric materials, such as films and fibers, may improve their surface properties and this improvement on PP active sites should initiate a surface postgrafting that can be formed by an EB irradiation. EB modified PP was also functionalized through an aging reaction, emphasized by a high radical concentration. Active surface films are susceptible to react with monomers in a postgrafting reaction (Poncin-Epaillard, Chevet, &

In this work, the PP fabric is irradiated with electrons to form oxygen containing groups on its surface. By creating these functional groups, the uncovered part of PP fabric can be dyed by cationic dyes easily without any hazardous materials (Shahidi et al, 2007). Thus, just by

The aim of this research is the development of an environmental-friendly process with no

Due to low surface energy, polypropylene has very weak hydrophilic properties and doesn't have any affinity to cationic dyes. In this study, some parts of polypropylene fabrics (PP) have been covered by mask, and then they were irradiated by electrons with different energies (Figure 7). After electron irradiation, the samples have dyed with cationic dyestuff. The electron irradiated parts can be dyed and by this work we can print or decorate the polypropylene fabrics and films easily. The treated surfaces were characterized by Scanning Electron Microscopy (SEM), reflective spectroscopy and FTIR. Also, light and wash fastnesses of printed samples were measured. As we know, pigment printing method requires additional materials such as gauze, screen, screen frame, screen lake, etc. and these affect product costs. Moreover, this process requires longer times compared to Electron Beam (EB) designing. On this account EB designing is more advantageous. One of the advantages of the EB designing is the good repeatability of the designs. Besides, desired physical effects can be fully ensured. In pigment printing method printing time is lengthening and reproducibility decreases due to the difficulties such as paste preparation, squeegee motion, clogging of the screen and the necessity to print the same area for each sample. Moreover, EB designing process does not include any after-treatments such as

thickeners in order to enable good quality printing and to minimize water pollution.

Halasz, & Czvikovszky, 2003).

dyeing the fabrics can be printed.

Brosse, 1994).

drying and fixating which increase the production time and costs. The results from this work show that the EB-based designing process represents a serious competitor of the conventional technologies. And just by dyeing the electron irradiated samples, the printed look appeared on the surface of PP fabrics, it is because of this matter that, PP doesn't have any affinity to cationic dyestuffs, but after EB treatment, cationic dye can be absorbed by irradiated parts of fabrics easily.

Fig. 7. The Schematic view of experimental setup.

In order to study the chemical modification of the electron irradiated part of fabrics, Fourier transform infrared spectroscopy is used. FTIR was used to examine the functional groups of the corresponding samples investigated in Figure 8. As shown only slight increase in absorbance at 1720 cm−1 (C=O) band and 3400 cm−1 (O-H) band and 1080-1300 cm-1 (C-O) after electron irradiation can be noticed. The improvement of dye-ability properties of these uncovered parts confirmed that, electron bombardment activated successfully the surface of uncovered PP fabrics. The main effect of electron beam treatment of a polymer is the transfer of energy towards the respective polymer surface .In function of the molecular structure of the polymer, one of the following events could proceed : crosslinking , chain scission or radical stabilization. In the case of polymer treatments by Electron Beam, electrons are accelerated towards the exposed surface and lead to an increased reactivity of the respective surface. This fact is possible due to the breaking of the different bonds and further formation of free radicals. After the polymer samples are brought out from the reactor, the reaction of the oxygen from the atmosphere with the free radicals takes place, and thus surface functionalization is obtained. This

Effect of Plasma on Dyeability of Fabrics 337

Fig. 9. The photo of printed samples

**4. Ion beam modification of polypropylene fabrics** 

The main goal of this work was examination of structural and compositional changes in the polypropylene (PP) fabrics caused by ion irradiation. In this work, the PP fabric has been irradiated with CO2 ions. The implantation conditions (i.e, exposure time, beam current, and discharge power) were changed to control the extent of surface modification. And the effects of irradiation were studied using different instruments. Also dye ability of the untreated sample and treated under different conditions were investigated by using a 3% wt aqueous solution of a basic dyestuff. The obtained data show that, ion beam processing of PP fabrics allows an adjustable modification of their surface properties. The functional groups on the surface of samples were examined using FTIR spectrometer. Moreover, dyeing properties for treated fabrics have been tested. Significant increase in color strength has been achieved. Morphology of samples was examined by Scanning Electron Microscopy (SEM). The PP fabric was mounted on a sample holder and placed inside a vacuum system Fig 10. Carbon dioxide ion beams at energies of 1 and 2 keV were implanted, using an Ion Beam Sputtering system with Kauffman Ion Source, at the Plasma Physics Research Center (Tehran, Iran). Vacuum chamber was evacuated to the base pressure of 9 10-3 torr using rotary pump, and then to pressure of 10-5 torr using turbo pump. After filling the chamber with 10-2 torr of

functionalization is more important for the materials that have no oxygen-containing groups in their initial composition. The improvement of dye-ability properties of these uncovered parts confirmed that, electron bombardment activated successfully the surface of uncovered PP fabrics.

Fig. 8. The FTIR results of untreated and treated samples.

In this study, Electron Beam Irradiation has been used as a novel method for decoration of PP Fabrics. The highest relative color strength (K/S) is obtained and the fastness properties range between good and excellent for samples printed using electron irradiation, this is true irrespective of the type of printed fabric. In this research work, the physical and chemical properties of PP fabrics were improved by using electron beam irradiation with different energy of bombardment. By this treatment, the wet ability and Dye ability of PP were increased significantly through creating (-O-H), (C=O) and (C-O) groups on the surface of samples where hydrophobic properties changes to hydrophilic.

And we could dye the uncovered electron irradiated parts of PP fabrics with cationic dyestuff and decorate the PP fabrics without any thickener and auxiliaries as it can be seen in Figure 9(d). It is expected that, EB irradiation which has been known for a long time and is being used in different branches of industry, in the near future will conquer polymer as well (Payamara et al, 2010).

functionalization is more important for the materials that have no oxygen-containing groups in their initial composition. The improvement of dye-ability properties of these uncovered parts confirmed that, electron bombardment activated successfully the surface

of uncovered PP fabrics.

Fig. 8. The FTIR results of untreated and treated samples.

samples where hydrophobic properties changes to hydrophilic.

well (Payamara et al, 2010).

In this study, Electron Beam Irradiation has been used as a novel method for decoration of PP Fabrics. The highest relative color strength (K/S) is obtained and the fastness properties range between good and excellent for samples printed using electron irradiation, this is true irrespective of the type of printed fabric. In this research work, the physical and chemical properties of PP fabrics were improved by using electron beam irradiation with different energy of bombardment. By this treatment, the wet ability and Dye ability of PP were increased significantly through creating (-O-H), (C=O) and (C-O) groups on the surface of

And we could dye the uncovered electron irradiated parts of PP fabrics with cationic dyestuff and decorate the PP fabrics without any thickener and auxiliaries as it can be seen in Figure 9(d). It is expected that, EB irradiation which has been known for a long time and is being used in different branches of industry, in the near future will conquer polymer as

Fig. 9. The photo of printed samples
