苎麻生物脱胶与化学脱胶精干麻纤维性能对比

从化学成分、物理性能和微观结构方面对经生物脱胶和化学脱胶的苎麻精干麻纤维进行了比较,研究表明:经生物脱胶后的精干麻纤维的残胶率略高于化学脱胶精干麻,但其强力增大,柔软性、卷曲弹性和表面摩擦性能均有一定程度的改善.     

苎麻生物脱胶精干麻的纺纱性能研究

对苎麻生物脱胶精干麻的纺纱性能进行了研究,并与化学脱胶精干麻的纺纱性能进行了比较.结果显示,生物脱胶精干麻的纺纱性能要好于化学脱胶精干麻,且成纱强力高,条干好,毛羽少,质量指数高.     

蒽醌助剂对乙二醇溶剂脱胶苎麻纤维性能的影响

为解决苎麻在乙二醇有机溶剂脱胶中纤维易被氧化而导致性能下降的问题,在乙二醇溶剂中添加助剂蒽醌对苎麻进行脱胶,并对蒽醌不同添加量下制得的纤维进行结构和性能表征。结果表明:纤维中半纤维素含量随蒽醌添加量的增加而升高,纤维的聚合度、结晶度、物理力学性能先升高后降低,纤维的残胶率和线密度先降低后升高;当蒽醌质量分数为0.3% 时,这些性能均达到最佳值,此时纤维的聚合度、结晶度、制成率、断裂强度、断裂伸长率、断裂功比不加蒽醌时分别提高了7.32%、20.53%、1.46%、9.55%、6.89%、33.33%,纤维的残胶率、线密度比不加蒽醌时分别降低了17.91%、7.24%。     

采用N-甲基吡咯烷酮的苎麻纤维柔软处理

为提升苎麻纤维的柔软性,采用N-甲基吡咯烷酮(NMP)对其进行处理。探讨不同NMP质量分数、处理时间和温度对苎麻纤维强伸性能和柔软性能的影响,并借助X射线衍射仪、红外光谱仪和扫描电子显微镜对苎麻纤维进行表征与分析。结果表明:当NMP质量分数、处理时间或温度任一因素增加,苎麻纤维的断裂伸长率随之增加,而断裂强度随之降低;当NMP质量分数或处理时间增加时,苎麻纤维的断裂回转数会先增加后减少,当处理温度升高时,断裂回转数会先增加后保持稳定;在NMP质量分数为15%,处理时间为60 min,处理温度为80 ℃的较佳工艺条件下,处理后苎麻纤维的结晶度从80.37%降至70.19%,而其化学基团保持不变,纤维表面纵向沿竖纹出现劈裂。     

莲纤维的物理性能

为了解莲纤维的基本物理性能,为莲纤维织物的开发提供理论参考,对莲纤维的密度、线密度和回潮率等基本物理性能进行测试。研究表明:莲纤维的密度为1.1848 g/cm3,远比棉、苎麻及羊毛的密度小,与蚕丝、腈纶接近;莲纤维的线密度为1.55 dtex,远小于苎麻、蚕丝,与棉纤维及棉型化纤的线密度较接近,说明莲纤维较细,有利于成纱强力和条干均匀度,可纺高支纱;莲纤维回潮率为12.32%,比棉、蚕丝高,比羊毛、粘胶要低,与苎麻接近,说明莲纤维具有很好的吸湿性。     

Influence of low-temperature plasma treatment on properties of ramie fibers

In this study, ramie fibers were treated under various low-temperature plasma conditions such as different output powers (100, 150, 200, 250, and 300 W) and irradiation times (1, 1.5, 2, 2.5, and 3 min). The effects on fiber surface morphology, contact angle, friction and tensile properties were investigated. The results showed that properties of ramie fibers changed significantly after low-temperature plasma treatment. Compared with the untreated fibers, surface free energy increased 117.0 and 122.9%, friction coefficient improved 10.7 and 13.4% after 1 min-300 W and 3 min-100 W treatment. However, with the higher output power and the prolonged treatment time, low-temperature plasma treatment may cause damage to the tensile property of ramie fiber. Scanning electron microscopy showed that pectin and impurities covering of fibers were removed after low-temperature plasma treatment and alkali treatment, and the surface of ramie fiber was etched by low-temperature plasma treatment. Based on the analysis of experimental results, three groups (1 min-100 W, 2 min-150 W, and 3 min-200 W) were chosen as the following treatment process and compared with alkali treatment. It was found that properties of ramie fibers had more significant change after low-temperature plasma treatment.     

N-甲基吗啉-N-氧化物处理苎麻纤维工艺的优化

为提高N-甲基吗啉-N-氧化物（NMMO）对苎麻纤维的处理效果,利用正交试验方法优化了其处理工艺,通过测试处理后纤维性能得出：温度为65 ℃、NMMO 质量分数为 30%、处理时间为 20 min 时苎麻纤维的综合性能达到最佳;处理后纤维中既无 NMMO 分子残留,也没有生成新的纤维素;最佳工艺条件下,苎麻纤维的断裂强度和结晶度分别下降了23.84%和21.08%,线密度、断裂伸长率和断裂回转数分别增加了11.05%、41.36%和57.53%,苎麻纤维的综合性能较未处理时有较大提升。     

Study on length distribution of ramie fibers

The extra-long length of ramie fibers and the high variation in fiber length has a negative impact on the spinning processes. In order to better study the feature of ramie fiber length, in this research, the probability density function of the mixture model applied in the characterization of cotton fiber length was used to fit the ramie fiber length distribution tested by the Y131 wool fiber comb stapling sorter. Furthermore, the generation of ramie fiber length distribution with the commonly used ramie fiber length parameters was also studied, and it was concluded that ramie fiber length distribution could be generated by the corresponding tested fiber length parameters.     

丹蒽醌对氧化脱胶苎麻纤维理化性能的调控

为解决苎麻氧化脱胶中纤维容易被过度氧化而性能受损的问题,在氧化脱胶液中添加了具有纤维素和半纤维素保护效果的试剂 1,8-二羟基蒽醌（丹蒽醌）,并通过调节1,8-二羟基蒽醌的用量实现了对苎麻纤维理化性能（强伸性能、聚合度、半纤维素含量、制成率等）的调控。结果表明,1,8-二羟基蒽醌用量越高,纤维中半纤维素含量、制成率越高;但纤维强伸性能随1,8-二羟基蒽醌含量先升高后降低;当1,8-二羟基蒽醌的用量为2 %时,脱胶的综合效果最佳,此时纤维的断裂功、聚合度、半纤维素含量、制成率比不使用1,8-二羟基蒽醌时分别提高了41.0%、2.0%、17.3%、7.0%;此外,使用1,8-二羟基蒽醌后,脱胶废水的COD值降低了40%,大幅度提高了氧化脱胶工艺的环保性。     

苎麻纤维复合材料力学性能的研究

利用化学脱胶方法制得全脱胶苎麻纤维,发现全脱胶苎麻纤维较原苎麻纤维的分散性更好,断裂伸长率更高。制备全脱胶苎麻纤维体积分数分别为10%、20%、30%,树脂基体分别为环氧树脂和聚丙烯的复合材料,测试其压缩、弯曲、剪切性能,观察断面情况;然后分析纤维含量及树脂种类对复合材料力学性能的影响;并根据其用途方向,最终确定全脱胶苎麻纤维体积分数在20%时的苎麻/环氧树脂复合材料的综合性能最佳,适用于医用夹板材料。