Improving the dyeability of polyimide by pretreatment with alkali.

Polyimide fabric, as a high-performance fabric, possesses advantageous properties, such as outstanding thermal stability and chemical resistance, but has poor dyeability. In this paper, polyimide fabric was dyed successfully with disperse dyes by high-temperature and high-pressure dyeing in the presence of a swelling agent and auxiliaries. Under optimal dyeing conditions, it is pretreated with Na OH 6 g l⁻¹ and dyed with disperse dyes 5% o.w.f., NaCl 1 m, benzyl alcohol 60 ml l⁻¹ at 135 °C for 45 min to obtain a satisfactory colour yield with good washing fastness and dry rubbing fastness with 93.3% strength retention. The experimental results demonstrate that the Nernst adsorption isotherm is a favourable model for polyimide fabric dyeing with disperse dyes. [ABSTRACT FROM AUTHOR]