P. S. R. Choi

Determining Functional Groups of Commercially Available Ink-Jet Printing Reactive Dyes Using Infrared Spectroscopy

An infrared (IR) spectroscopic technique was used to determine the possible functional groups and chemical compounds present in commercially available ink-jet printing reactive dyes of four primary colours, i.e. Cyan, Magenta, Yellow, and Black. Although other instrumental analytical methods can help to determine the actual chemical composition of reactive dyes, the IR technique alone can still provide important structural information about the commercially available reactive dyes. Experimental results revealed that the reactive dyes under determination contained the same functional groups and chemical compounds as the reference reactive dyes.

USING NANO-TiO2 AS CO-CATALYST FOR IMPROVING WRINKLE-RESISTANCE OF COTTON FABRIC

In order to prevent cotton wrinkling, hydroxyl groups in the cellulose chain of cotton are partially crosslinked to keep the chain fixed relative to each other with dimethylol dihydroxy ethylene urea (DMDHEU). However, DMDHEU suffers disadvantages of reduced fabric strength and releasing of free formaldehyde. Recently, 1,2,3,4-butane tetracarboxylic acid (BTCA) has been explored as a new wrinkle-resistant agent providing similar performance to that of DMDHEU. In BTCA finishing, catalyst of inorganic phosphorus-containing acids was used but such phosphorus compounds have an adverse impact on the environment. In this paper, nano-TiO2 was used as a co-catalyst with sodium hypophophite in the treatment of cotton with BTCA, and the final properties were assessed.

The effect of the pretreatment print paste contents on colour yield of an ink-jet printed cotton fabric

Optimum condition concerning the content of pretreatment print paste and steaming time for ink-jet printing was newly developed through the orthogonal analysis. The cotton fabric treated under the newly developed optimum condition could achieve a high level of colour yield similar to that of the commercially pretreated cotton fabric available in the market for ink-jet printing. The results were discussed thoroughly in this paper.

Improvement of wrinkle-resistant treatment by nanotechnology

In this research, the non-formaldehyde wrinkle-resistant treatment of cotton fabrics has been investigated using the 1,2,3,4-butane tetracarboxylic acid as cross-linking agent and sodium dihydrogen hypophosphite as catalyst together with nano titanium dioxide as co-catalyst compound. The effect of changes in the concentration of 1,2,3,4-butane tetracarboxylic acid and nano titanium dioxide on the wrinkle recovery angle, tensile strength, tearing strength and bending length of cotton fabrics was evaluated. It was found that the addition of nano titanium dioxide could enhance the wrinkle resistance and decrease the bending length of the cotton fabric with little effect on the tearing and tensile strength of the treated fabrics.

Digital ink-jet printing for chitosan-treated cotton fabric

In this paper, chitosan was suggested for using as a replacement for sodium alginate in the pretreatment print paste for digital ink-jet printing for cotton fabric. Pretreatment print pastes prepared from the mixture of chitosan and acetic acid with the appropriate viscosity gave satisfactory prints on the cotton fabric. Chitosan-treated cotton fabrics were digitally irk-jet printed with four different colors and the color fastness rating of the printed fabrics was satisfactory. Experimental results revealed the possibility of pre-treating the cotton with chitosan to replace the sodium alginate normally present in the pretreatment print paste recipe.

A STUDY OF THE FACTORS AFFECTING THE COLOUR YIELD OF AN INK-JET PRINTED COTTON FABRIC

Optimum conditions involving the contents of the pretreatment print paste and the steaming time for ink-jet printing were newly developed through orthogonal analysis. Cotton fabric treated under the newly developed optimum conditions could achieve a high colour yield for ink-jet printing similar to that of the commercially pretreated cotton fabric available in the market. The results are discussed thoroughly in this paper.

Polyester metallisation with electroless silver plating process

In this paper, electroless silver plating process for polyester was reported. The electroless silver plating is basically divided into four stages including pre-cleaning, sensitisation, electroless silver deposition and post-treatment. As the electroless silver plating stage is the key stage in affecting the brilliant appearance and various functional properties such as conductivity and ultra-violet protection, we will study the effect of process variables, i.e. amount of silver nitrate (AgNO3), concentration of ammonium hydroxide (NH4OH), concentration of sodium hydroxide (NaOH) and process temperature, using increased amount of silver in fabric surface as an indicator, for optimising the electroless silver plating process for possible industrial application. Experimental results revealed that amount of silver nitrate (AgNO3)=1.77×10−3 mole; concentration of ammonium hydroxide (NH4OH)=6.25 %; concentration of sodium hydroxide (NaOH)=0.008 g/ml and process temperature=25 °C can give the best electroless silver plating for polyester fabric. The surface characteristics of the electroless silver-plated polyester fabric were evaluated by scanning electron microscope, X-ray photoelectron spectroscopy and X-ray diffraction analysis. Meanwhile, the performance properties of the electroless silver-plated polyester fabric were measured by CIE L*, a* and b* values, conductivity as well as ultraviolet protection. The experimental results would be discussed thoroughly in this paper.

A two-bath method for digital ink-jet printing of cotton fabric with chitosan

In our previous research, the possibility of using chitosan in preparing the pretreatment print paste for digital ink-jet printing for cotton fabric was investigated but the final color was not good as expected. In this paper, we modified our previous work by applying the chitsoan separately on the cotton fabric for digital ink-jet printing. A two-bath method was thus proposed and it was confirmed that a better color yield was achieved with this method. However, the use of chitosan reduced the tensile strength of the digital ink-jet printed fabric slightly.

Effect of low-temperature plasma pre-treatment on the chemical silver-plated polyester fabrics

Low-temperature plasma (LTP) has been increasingly employed for polymer surface modifications. In this paper, plasma gases of oxygen and argon were used for pre-treating polyester fabrics before conducting chemical silver plating, aiming to increase the amount of metal content and improve the performance of the polyester fabrics. After LTP pre-treatment, there was a thin plasma layer generation on the fabric surface which was in good contact with the fibre. Based on the observation of micro-structure using scanning electron microscopy (SEM), it was found that there was an increase in the amount of silver particles deposited on the fibre surface after the LTP pre-treatment. The surface observation implies that the LTP pre-treatment could enhance the hydrophilicity of fibre surface and help facilitate the absorption of silver particle layer to reach the necessary level of uniformity and adhesive strength.

Functional Properties of Electroless Silver-Plated Cotton Fabric via LTP Pre-Treatment

Silver-plated textiles have exhibited their specific features not only on mechanical performance but also on functional properties. In this study, silver plating technique was applied on cotton fabric to improve its functional properties, especially the anti-bacterial and anti-UV properties. Silver plating was conducted in this research with the aid of oxygen and argon low-temperature plasma (LTP) pre-treatment on the cotton fabric to manipulate the film of the coating. The silver-plated cotton fabric was characterized in terms of its functional properties. The micro-roughness formed on the cotton fabric after the LTP pre-treatment facilitated the silver particles deposition. As a result, the anti-bacterial and anti-UV properties of the silver-plated cotton fabric and the water repellent ability of the cotton fabric were improved after the silver-plating process.