Polyimide (PI) fiber is one kind of high-performance fibers with outstanding thermal stability, mechanical properties, and chemical resistance, but it is difficult to be dyed due to its tightly packed macromolecules and lack of functional groups for dyeing. Especially, the inherent yellow shade of PI fiber limits the color gamut that can be matched by trichromatic dyeing. In this study, it is proposed to investigate the possibility to dye PI fibers into a black shade with disperse dyes and basic dyes with the assistance of swelling agents. The dyeing experiments showed that, among the proposed swelling agents, N-methyformanilide (MFA) was the preferred candidate for enhancing the dyeing ability of PI fibers. Using the inherent yellow color of PI fiber as a yellow component in trichromatic dyeing it could be dyed into a black shade with good colorfastness to washing, rubbing, and dry-heating. In spite of causing a slight decrease in tensile strength the dyeing would not impair the thermal stability of PI fibers.

聚酰亚胺（PI）纤维是一种具有出色的热稳定性，机械性能和耐化学性的高性能纤维，但由于其紧密堆积的大分子和缺乏用于染色的官能团，因此难以染色。特别是，PI纤维固有的黄色阴影限制了三色染色可以匹配的色域。在这项研究中，建议研究在溶胀剂的帮助下用分散染料和碱性染料将PI纤维染成黑色的可能性。染色实验表明，在提出的溶胀剂中，N-甲基甲酰苯胺（MFA）是增强PI纤维染色能力的首选。使用PI纤维固有的黄色作为三色染色中的黄色成分，可以将其染色为黑色，具有良好的耐洗，耐擦和干热色牢度。尽管会导致拉伸强度略有下降，但染色不会损害PI纤维的热稳定性。