【摘要】 聚乳酸(PLA)与聚(3-羟基丁酸酯-co-3-羟基戊酸酯)(PHBV)共混纺丝是改善聚乳酸(PLA)纤维的耐热性和柔韧性的方法之一。为了揭示共混纤维结构对其织物染色性能的影响规律，借助热重分析仪、差示扫描量热仪、X射线衍射仪等手段分别对共混纤维和PLA纤维的微结构和热性能进行分析。采用高、中、低温3类分散染料，对2类纤维织物的染色升温速率曲线、提升性和各项染色牢度等性能进行了比较。结果表明：共混纤维中PLA与PHBV两相分离，PLA相具有与PLA纤维相似的晶型结构，其结晶度较高，而PHBV相中形成较低的结晶；与PLA纤维相比，共混纤维的熔点较高，玻璃化温度稍低，因此其能在较低的温度下达到上染平衡；在相同的染色条件下，共混纤维织物的表观染色深度几乎是PLA织物的2倍；2类纤维织物的耐皂洗色牢度性能均不够理想。更多还原

【Abstract】 Objective In order to improve the heat resistance and flexibility of polylactic acid(PLA) fibers, the polylactide(PLA)/3-hydroxybutyrate-co-3-hydroxyl valentate(PHBV) blend fibers is one of the wildly used methods which received increasing attention. The literature for their preparation process, microstructure and mechanical properties were frequently found. But the relationship between the microstructure and dyeing properties lacked systematic investigation. The aim of this work is to explore the effect of structure for PLA/PHBV blend fibers on the dyeing properties of disperse dyes for their fabrics with a comparison to that of PLA fibers.Method By using the thermal weight, differential scanning calorimeter and X-ray diffraction methods, the crystallization and thermal properties including glass transition, melting temperature and thermal stability for the PLA/PHBV blend fibers and PLA fibers were investigated, respectively. The dyeing properties such as dyeing rate, build-up and color fastness of two fabrics were measured with three different types of disperse dyes which corresponded to the grades of low, medium and high energy, respectively. Results The analysis of X-ray diffraction showed that the pattern of peaks(16.74°, 19.30°) for the PLA/PHBV blend fibers was similar to that for the PLA fibers(16.68°, 18.90°) except a small peak at 13.82° being found(Fig.2). The crystallinity for PLA component(83.16%) was larger than the PLA fibers(77.14%). Based on the results obtained from previous research, it was confirmed that there were microphase separation between PLA and PHBV component, the small diffraction peak was derived from the PHBV component, which formed lower crystallinity. The measurement of the differential scanning calorimeter revealed that the glass transition temperature of the PLA/PHBV blend fibers(72.21 ℃) was slightly lower than that of the PLA fibers(74.85 ℃)(Fig.3), while the melting temperature(167.46 ℃) was slightly higher than that of the PLA fibers(166.35 ℃). The analysis of thermal weight illustrated that the thermal decomposition for the PHBV component in blend fibers occurred at the temperature of 280.67 ℃, and at 358.39 ℃ for PLA component, which was higher than that for the pure PLA fibers(343.30 ℃), which may be caused by its higher degree of crystallinity(Fig.4). In addition, the results for dyeing properties showed that the blend fiber has a lower dyeing transition temperature(T_D) than the PLA fibers, and can reach the dyeing equilibrium at a lower temperature(Fig.5). In the case of high-energy grade disperse dyes, the Dyeing transition temperature(T_D) was 70 ℃ for the blend fibers and 80 ℃ for the PLA fibers, and the temperature of dyeing equilibrium was 100 ℃ for the blend fibers and 110 ℃ for the PLA fibers. Under the same dyeing conditions, the apparent color depth value of the dyed blend fabric was almost twice that of the dyed PLA fabric(Fig.6), and its soap washing fastness performance was not good enough as the PLA fibers, especially for the staining fastness on wool, nylon and acetate fibers was only 1-2 rate(Tab.1).Conclusion It was concluded that two components in blend fibers were in the form of microphase separation, the PLA phase had a similar crystal structure and a higher crystallinity compared to that of the PLA fibers, and the PHBV phase formed a small number of crystal structures. Therefore, PLA/PHBV blend fibers had a slightly higher melting point and lower glass transition temperature than PLA fibers, while PLA components had higher decomposition temperatures than PLA fibers, but the PHBV component was lower than the PLA components. Owing to the lower glass transition temperature, the blend fibers exhibited a higher dyeing rate than the PLA fibers. Under the same dyeing conditions, the color of the fabric derived from PLA/PHBV blend fibers was deeper than that of PLA fabric, and the apparent color depth value of the former was generally about 2 times that of the latter due to higher amorphous area in blend fibers. The color fastness properties for the fabric from the blend fibers was not desirable. Further research is needed to improve its dyeing properties to promote the development and application of these biodegradable fibers.更多还原