The physico-chemical behavior of disperse dye is the crucial point and basis for utilization CO₂ in supercritical state as an environmentally friendly waterless dyeing medium, which has triggered widespread concern. In the present work, the physico-chemical behavior of Disperse Red 167 was investigated in supercritical CO₂, for the first time. Scanning electron microscopy results show that the melting of Disperse Red 167 was observed with CO₂ temperature increasing from 120 °C to 160 °C. Fourier transform infrared spectrometry spectra reveal that the slight shifts and differences in the intensities of the characteristic bands of Disperse Red 167 was presented before and after supercritical CO₂ treatment. XRD and TG analysis indicate that crystal form of Disperse Red 167 transformed from β-type to ɑ-type due to the dissolution and melting recrystallization, and the thermal decomposition temperatures were shifted to a lower temperature when the CO₂ temperature was higher than 120 °C. Moreover, dyeing experiments with the recycled Disperse Red 167 samples present similar colorimetric values and colorfastness properties to original dye. Therefore, all the investigations further offer the evidence that the melting recrystallization of disperse dyes occurred under higher temperature condition in supercritical CO₂, which confirms the recycling performance of disperse dye, and also provides the feasibility for thermosol dyeing in supercritical CO₂.

分散染料的物理化学行为是将超临界状态的CO ₂用作环境友好型无水染色介质的关键和基础，已引起广泛关注。在本工作中，首次研究了分散红167在超临界CO _2中的理化行为。扫描电子显微镜结果表明，随着CO ₂温度从120℃升高到160℃ ，观察到分散红167的熔化。傅里叶变换红外光谱表明，在超临界CO ₂前后，分散红167的特征谱带强度发生了微小的变化和差异。治疗。XRD和TG分析表明，分散红167的晶型由于溶解和熔融重结晶从β型转变为ɑ型，当CO ₂温度高于120°时，热分解温度转变为较低的温度。C。此外，使用回收的分散红167样品进行的染色实验显示的色度值和色牢度特性与原始染料相似。因此，所有的研究进一步提供了证据，表明分散染料的熔融重结晶在较高温度条件下在超临界CO _2中发生，这证实了分散染料的再循环性能，也为在超临界CO _2中进行热溶胶染色提供了可行性。