Using Nano-TiO2 as Co-catalyst for Improving Wrinkle-resistant of Cotton Fabric

Abstract

Cotton contains cellulose molecules arranged linearly and passing through the crystalline and amorphous regions of the fibres. The cellulose molecules are held in position by hydrogen bonds between themselves. When a force of sufficient magnitude is applied onto the fibres, slippage occurs between the cellulose chains. The hydrogen bonds present between the cellulose molecules tend to resist or prevent the slippage. However, when slippage occurs, the hydrogen bonds reform at new locations and tend to maintain the fibre in a bent or wrinkle state. On the other hand, the absorption of water facilities the breaking of the hydrogen bonds and thus cotton wrinkles easily after laundering. In order to prevent cotton from wrinkling, hydroxyl groups in the cellulose chain of cotton are partially crosslinked to keep the chain fixed relatively to each other. The popular crosslinking agent recently in use is the dimethylol dihydroxy ethylene urea (DMDHEU). However, DMDHEU suffers a disadvantage that its reaction product on the fabric tends to decompose and release formaldehyde which cause harm to human health. 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 such as sodium hypophosphite was used. However, such phosphorus compounds have a highly adverse impact on the environment such as causing an increase in growth of algae in rivers and lakes, thus lowering the oxygen content in water. In this paper, nano-TiO2 was used as a co-catalyst with the sodium hypophophite in the treatment of cotton with BTCA. The experimental results revealed that the wrinkle recovery of the cotton fabric was improved and the effectiveness of sodium hypophophite, with reduced amount, as a catalyst was improved by the addition of nano-TiO2.