Traditional polyurethane fibers (CPUF) are widely used in the preparation of blend clothing in order to improve the elasticity and comfort of fabrics. However, there has been a problem of low acid dye adsorption for CPUF, resulting in light hue of dyed CPUF. In this work, a poly (HMDI-BHOPA) was prepared with dicyclohexylmethane 4,4′-diisocyanate (HMDI) and 1,4-(2-hydroxyethyl) piperazine (BHOPA), and then added into the CPUF spinning solution for the preparation of modified polyurethane fibers (BPUFs) through dry-spinning technology. Tertiary amine groups were introduced after the addition of poly (HMDI-BHOPA), which could be protonated at acidic conditions to form binding sites for acid dyes, further enhancing the adsorption capacity of the fibers. Nuclear magnetic resonance spectroscopy (1H and 13C NMR) was used to confirm the structure of poly (HMDI-BHOPA). The results of differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) demonstrated that the addition of poly (HMDI-BHOPA) had little effect on the glass transition temperature and thermal stability of BPUFs. The addition of poly (HMDI-BHOPA) affected the ordered arrangement of hard segments and reduced crystallization enthalpy of hard and soft segments in polyurethane. Hence, the elastic recovery of BPUFs showed little change, and the elongation at break and break strength decreased compared to CPUF. Zeta potential testing results showed that BPUFs was protonated under acidic conditions. Dyeing results proved the enhancement of dyeability of BPUFs. The dyeing kinetics and thermodynamics of acid dyes on BPUFs were studied to investigate the dyeing mechanism. From the dyeing kinetics results, both CPUF and BPUFs fitted Elovich model. From dyeing thermodynamics results, Langmuir model showed a better applicability for BPUFs at a low pH and temperature condition, while Freundlich model fitted better for CPUF.

中文翻译：

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通过引入质子化叔胺基团增强聚氨酯纤维的染色性


传统的聚氨酯纤维（CPUF）广泛用于混纺服装的制备，以提高织物的弹性和舒适度。但CPUF一直存在酸性染料吸附性低的问题，导致染色后的CPUF色调偏浅。本工作以二环己基甲烷4,4'-二异氰酸酯(HMDI)和1,4-(2-羟乙基)哌嗪(BHOPA)为原料制备了聚(HMDI-BHOPA),并将其添加到CPUF纺丝溶液中制备通过干纺技术生产改性聚氨酯纤维（BPUF）。添加聚(HMDI-BHOPA)后引入叔胺基团，在酸性条件下可质子化，形成酸性染料的结合位点，进一步增强纤维的吸附能力。核磁共振波谱（1H和13C NMR）用于确认聚（HMDI-BHOPA）的结构。差示扫描量热法(DSC)和热重分析(TGA)结果表明，聚(HMDI-BHOPA)的添加对BPUF的玻璃化转变温度和热稳定性影响不大。聚(HMDI-BHOPA)的添加影响了聚氨酯中硬链段的有序排列，降低了硬链段和软链段的结晶焓。因此，与 CPUF 相比，BPUF 的弹性恢复几乎没有变化，断裂伸长率和断裂强度有所下降。 Zeta电位测试结果表明，BPUF在酸性条件下发生质子化。染色结果证明BPUF的染色性得到增强。研究了酸性染料在 BPUF 上的染色动力学和热力学，以探讨染色机理。从染色动力学结果来看，CPUF 和 BPUF 均符合 Elovich 模型。 从染色热力学结果来看，Langmuir 模型在低 pH 和温度条件下对 BPUF 表现出更好的适用性，而 Freundlich 模型则更适合 CPUF。