【作者】 薛丽；

【导师】 唐人成；

【作者基本信息】 苏州大学 ， 纺织化学与染整工程， 2007， 硕士

【摘要】 聚乳酸纤维(PLA纤维)作为最受青睐的可生物降解的化学纤维,以其优良的性能和广泛的应用赢得了人们的关注,其染整加工基础理论具有较深的研究意义。本课题主要对聚乳酸纤维的染色性能及染色过程中纤维结构的变化做了探讨,并得出如下结论:对本实验所用聚乳酸(PLA)纱线的结构进行表征,并与聚对苯二甲酸丙二醇酯(PTT)纱线和聚对苯二甲酸乙二醇酯(PET)纱线比较后发现,PET和PTT结构相似,PLA与之相比差异较大,且区别明显。在PLA纤维的染色性能研究方面,随着染色温度的提高,分散染料在PLA纤维上的上染率都有明显的上升趋势,但鉴于高温染色对纤维损伤过于严重,虽然高温染色有利于染料在纤维上的饱和值提高,染色温度还是不要超过110℃;对于PLA纤维的提升性能,偶氮类分散染料的提升性能明显好于蒽醌类分散染料,这与分散染料染涤纶的提升性能较为相似;分散染料在PLA纤维上的色光与在PET和PTT纤维上的色光相比,色相向短波方向移动;测定了十余只染料的升温上染速率曲线,偶氮苯分散染料在PLA纤维上的上染速度快于蒽醌染料;关于染料的无机性/有机性值(I/O值)与染色性能的关系,随着染料I/O值的下降,染料的上染百分率是逐渐增大的;与PLA纤维具有相近I/O值的分散染料具有更好的提升性能,从分散染料的上染百分率和提升性两方面综合考虑,挑出了对PLA纤维具有较好染色性能的三原色,橙30、红54或/和红74、蓝148。有关聚乳酸纤维在染色过程中的结构变化的探讨中,作者发现,经90-130℃空白高温染液处理的PLA纤维,随着处理温度的升高,熔融热逐渐增大,表明纤维的结晶度越来越大,纤维的热降解最大吸热峰峰温先降低、后升高,但均比原样低,这与纤维发生一定程度的降解后,结晶度增大有关系;X-射线衍射进一步表明纤维结晶度随处理温度的升高而增大;断裂强力和断裂延伸率随处理温度的升高而降低,120℃和130℃时发生了显著的降低。经100℃和110℃下不同时间空白高温染液处理的PLA纤维,其结构变化规律相似,只是在110℃下变化的程度更大。随着处理时间的延长,外推熔融起始温度、熔融温度、次熔融峰峰温以及热降解最大吸热峰峰温都呈下降趋势,熔融热都呈增大趋势,这表明虽然纤维的结晶度随着处理时间的延长而增大了,或者结晶状况随着处理时间的延长更加完善了,但是同时纤维降解得越来越厉害了;X-射线衍射进一步表明纤维结晶度随处理时间的延长而增大。总之,处理温度和时间均对聚乳酸纤维的结构变化有显著影响。更多还原

【Abstract】 Being a most popular hydro and biodegradable material, poly(lactic acid) fiber draws much attention for its excellent properties. The research on its dyeing properties and structures is of much importance for the development of PLA fiber. In this paper, the dyeing properties of PLA fiber and the changes in its structures during the dyeing process were investigated. The research results obtained are as follows.The structure character of PLA fiber that we used in this thesis had an obvious distinction compared with the PTT and PET fibers which also belong to the family of polyester fiber. This maybe due to the fact that there are no benzene rings in PLA molecules while there are in other two fibers. And the similar molecule structures of the PTT and PET fibers lead to the similarities in various analysis. Therefore, it is easy to distinguish PLA fiber among these three fibers.Many basic experiments on the dyeing performance of PLA fiber were carried out. The effect of dyeing temperature on the uptake rate and visual color depth value was carried out. Though the rate and color depth increased with temperature, it is appropriate to treat under 110℃considering the extension strength and degradation of the fiber. The azobenzene disperse dyes showed a better building-up property on PLA fiber compared with anthraquinone dyes. In terms of the color shades on PLA PTT and PET fibers, the disperse dyes exhibited a difference and the maximum absorption wavelength shifting to a shorter range on the PLA fiber. More than ten popular disperse dyes with different energy levels and chemical constitutions were used to compare their exhaustion, color yield on PLA fiber. The dyeing rates of azobenzene disperse dyes were faster than those of anthraquinone dyes. The color yields were inclined to increase with the decreasing I/O values of the disperse dyes. The dyes with similar I/O values to that of the PLA fiber appeared better building-up properties. A group of tricolor namely O 30, Red 54/Red 74 and Blue 148 was also recommended. The effect of dyeing temperature and time on fiber structure were investigated by DSC and WAXD analysis and strength test. It was observed that the melting enthalpy increased with the increase in dyeing temperature within 90-130℃, indicating that the degree of crystallinity increased with temperature. Meanwhile, the maximum degradation temperature decreased at first, and then went up when the dyeing temperature was higher. This may have something to do with both the reduced molecular weight and the increased crystallinity. The melting enhalpy increased and The onset melting temperature, maximum melting temperature decreased with dyeing time. The time had a more obvious influence on the changes in fiber structure than the temperature did. WAXD analysis indicated that the degree of crystallinity increased with the increase in dyeing temperature and the time.更多还原