| After half a century of development, polyester fiber has become an important raw material of textile industry. Polyester fiber is not only widely used in civilian areas, and industrial applications are increasingly important. In the conventional textile printing of polyester fabric, the disperse dye is applied with other additional chemicals in the form of a print paste. The print is then normally steamed to fix the dye onto the fabric and then washed thoroughly to remove any unfixed dye, chemicals and thickener. It was high consumption of dye, chemicals, water, steam and energy. And also it is ease to produce taking colour and bleeding, and so on. Polyester fabric inkjet printing technology is a clean printing method and it can reduce waste emissions and energy consumption. This technology can also promote the development of the whole textile printing. The prospects are broad.The technology of polyester fabric inkjet printing is usually classified into three categories: disperse dye inkjet printing, disperse dye transfer printing and pigment inkjet printing. It is necessary for disperse dye inkjet printing to undertake special pretreatment on the fabric before printing, and the final products must be achieved by steaming and washing. Disperse dye transfer printing is to print directly in the transfer paper, and then the dye transferred from paper to polyester fabric by heat sublimation. The technology has no pretreatment, steam washing and other post-treatment. There is no sewage disposal, and it is a simple process. But the dye utilization is not high and there are some difficulties in printing deep color patterns. A large amount of transfer printing paper will produce the pollution. Pigment-based inks printing undertake no special pretreatment on the fabric before printing. But the molecular structure of the poly(ethylene terephthalate) lacks polar groups, which causes it to have low surface free energy and poor wettability. When polyester fabric is printed with pigment-based inks, the printed patterns have poor color yield and easily bleeding, especially for thin fabric. As a result, the pretreatment process is necessary for the polyester fabric inkjet printing.Traditional pretreatment method was to use printing paste(such as sodium alginate, carboxymethyl cellulose, and so on) or cationic auxiliary (dodecyl trimethyl ammonium chloride, methyl benzyl ammonium chloride, benzyl triethyl ammonium chloride, and so forth). Although chemical modification of the fibers has been somewhat successful, there are environmental concerns related to the disposal of chemicals after treatment. Plasma treatment of polymeric fibers only affects their surface layer, and does not decrease intrinsic mechanical properties of textile materials. Plasma treatment is a clean, dry and environmental friendly physical technique.The radio frequency glow discharge low-temperature oxygen plasma treatment can change the surface properties of polyester fabric and the effect of plasma is related to the operating parameters. The optimum treatment condition was as follows: the power 80W, the processing time 7 min, and the pressure 40Pa. Compared to the untreated fabric, the wettability of the modified fabric was improved, and the wetting time was declined to 52s. Attenuated total reflection Fourier infrared spectroscopy (ATR FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses revealed that the element content of the fabric surface was changed. The C element content was decreased from the 75.9% to 59.3%, and the O element content was increased from 24.1% to 40.7%. The polar oxygen group was also increased. These polar groups will incorporate with moisture through hydrogen bonding and help moisture penetration and binding on the fabric surface, which enhances the wettability. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) photographs showed that the surface of fiber was etched and the smooth surface became rough. The warp and weft line width was decreased 35.3% and 43.9%, and the K/S values were increased by approximately 54%. So the pattern effect of ink jet printing was markedly improved. However, the radio frequency glow discharge is low pressure discharge, and it requires vacuum equipment. The energy consumption and costs are high. It is not a continuous process, and the practical applicability is limited.The atmospheric pressure dielectric barrier discharge plasma treatment can improve the hydrophilicity of the fabric surface by discharge treatment in air. The plasma treatment time and power was changed, and the performance of the pigment-based ink jet printing fabric was researched. In the experimental range, the optimum processing condition was as follows: the power 200W and the processing time l min. After plasma treatment, the weight loss of fabric was about 0.86%, and the wetting time was about 148s. The wettability of polyester fabric was increased. SEM and AFM photographs showed that plasma treatment caused the increase of surface roughness. XPS analyses revealed that plasma treatment introduced an amount of the oxygen containing polar groups on the fabric surface. At the same time, the warp line width was decreased 34.8%, and the weft line width was decreased 40.7%. Therefore, the inkjet printing performance of the fabric was improved. The surface modification effect and quality of ink jet printing was the same as of radio frequency discharge plasma treatment. The discharge was produced using ambient air and the process is simple and convenient, but also the cost is low.Plasma surface modification has obviously aging effect. It is necessary for the fabric to be inkjet printed after treatment. The inkjet printing effect of polyester fabric can be increased after plasma grafting treatment and also there is no aging effect. It is a convenient and simple pretreatment method. The optimum processing condition of RFGEP surface grafting was as follows: The concentration of acrylic acid and acrylamide was 35%, temperature of 30℃, and dipping 3h. The concentration of maleic anhydride was 15%, temperature of 70℃, and dipping 3h. The enhanced wettability was mainly contributed by some polar groups such as carboxyl and hydroxyl groups induced onto fabric surface through plasma grafting treatment. After grafting, the wetting time was decreased from about 20min to 6.44min, 4.39min and 2.81min respectively, and the contact angle was also decreased. The morphology of fiber and the surface chemical composition was changed, respectively. The warp and the weft line width were greatly decreased and the K/S values were enhanced. The inkjet printing performance was improved. APDBDP surface grafting has the same effect as of RFGEP surface grafting.In this paper,we also investigate the aging behavior of the plasma treated polyester fabric. The results showed that the surface modification of plasma treatment show the aging process. The fabric surface show a gradual hydrophobicity recovery over the time and the surface properties simultaneously decreases to the original value after plasma treatment. This is due to that the polar groups of the fabric surface were inversed to the body from the surface. The temperature and humidity that the fabric is stored play an important role in the aging process. As the temperature and the humidity are high,the sample exhibits a significant aging process. There is no obviously aging behavior for plasma grafting treated surface. This result indicates that the effect of plasma grafting is more stable than that of plasma surface processing.The surface performance of the polyester fabric was changed greatly after the plasma modification and plasma grafting. Due to the plasma etching smooth fiber surface became uneven. The wetting properties of the fabric were improved owing to the introduction of oxygen-containing polar groups. So it can be summarized that plasma treatment can enhance the quality of pigment ink jet printing technology. And also a new way was opened up for the promotion and application of pigment inkjet printing technology.
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