Saminathan Ratnapandian

Chapter 1

Introduction

1. Introduction

Humanity has progressed from the stone age to the information age and is now making deep inroads into the environment age [1]. This is characterised by increasing awareness regarding the effect of human interaction, both short and long term, with the environment. The extrapolated detrimental effect has evoked the need to conserve and protect our fragile environment. The growing public awareness has been expressed through an expanding premium market for goods and services that carry ‘natural’ or ‘eco-safe’ or ‘green’ or similar labels [2, 3]. Extensive research and development in science and technology are underway in order to satisfy this need. This provides an excellent focus point for the textile industry.

The textile colouration sector uses dyes (colouring matter), chemicals (whose reaction ensures the colouring of textiles) and auxiliaries (chemicals that promote colouration) in addition to consuming large quantities of water. Unfixed dye, spent chemicals and auxiliaries and water not picked up by the fibre material are collectively discharged at the end of colouration as effluent. Marine life would be adversely affected if these effluents, usually coloured, were discharged without treatment into the water body [4]. Further, such effluents affect riverbeds, soil and crops [5, 6]. This intimate relationship with the environment offers textile colouration the maximum scope for capitalising on the eco-conservation trend [7, 8].

Several authors [9-12] summarize the efforts of the colouration industry in embracing eco-conservation as:

1. 
   reducing the quantity of consumables by increasing process efficiency and reclaiming and reusing resources such as chemicals, water and energy
   
2. 
   using materials and processes with a lower environmental impact; and
   
3. 
   increasing the use of renewable resources such as natural fibres (silk, cotton and wool) and natural dyes.
   

This thesis contributes to the above effort by investigating the application of natural dyes employing the pad-dyeing process on cotton and wool. A comprehensive approach was adopted by evaluating either the use of plasma pre-treatment or the inclusion of chitosan for improving dye uptake during padding. On another front, the use of

comparatively benign auxiliaries was studied. In order to understand the scope of this research, a brief introduction to textile colouration is given below.

2.