N-甲基吗啉-N-氧化物改性对苎麻精干麻纤维染色性能的影响

苎麻精干麻纤维经N-甲基吗啉-N-氧化物(NMMO)溶液改性,考察NMMO溶液改性对苎麻纤维的断裂强力、纤维构架(红外光谱分析)及纤维染色性能的影响.结果表明,随着NMMO质量分数的升高,纤维断裂强力逐渐下降,最低降到29 cN;红外光谱表明苎麻纤维中羟基数量明显增加;染料上染苎麻纤维的上染率有明显提高而固色率稍微下降,但最终固色率还是提高了.当NMMO的质量分数为80%时,染料上染率提高了42%,固色率下降了5%,而最终固色率增加了25%.     

苎麻纤维在NMMO溶液中的溶胀与溶解

在不同N-甲基吗啉-N-氧化物(NMMO)体积分数[φ(NMMO)]、温度和时间条件下,考察苎麻纤维在NMMO水溶液中的溶解和溶胀情况.结果表明:在90℃条件下,当φ(NMMO)≥70%时,苎麻纤维被迅速切断并溶解,没有明显的溶胀现象;当φ(NMMO)=30%～60%时,苎麻纤维只发生溶胀,其溶胀增大率比水溶胀高;当φ(NMMO)20%时,苎麻纤维发生水溶胀.在60～80℃条件下,当φ(NMMO)=30%～80%时,苎麻纤维发生溶胀,其直径增大率最高达到210%;当φ(NMMO)20%时,苎麻纤维发生水溶胀,其直径增大率为100%.研究表明:随着处理时间的延长,苎麻纤维的直径增大率逐渐上升,达到最大值后保持不变;随着φ(NMMO)的增加,苎麻纤维的直径增大率升高;随着温度的升高,苎麻纤维直径增大率到达最大值的时间提前.     

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。     

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。     

NaOH-NMP处理对苎麻纤维性能的影响

为了改善苎麻纤维的柔软性能,采用NaOH和N-甲基吡咯烷酮(NMP)对苎麻纤维进行处理,分析了NaOH和NMP质量分数对苎麻纤维柔软性能和强伸性能的影响。随着NaOH和NMP质量分数的增加,纤维的断裂回转数和断裂伸长率逐渐增加,而断裂强度和初始模量逐渐降低。最优处理工艺为:NaOH质量分数6%,NMP质量分数10%,此时苎麻纤维的断裂回转数为467次,断裂强度为5.20 cN/dtex,断裂伸长率为3.89%,初始模量为139.13 cN/dtex,相比处理前断裂回转数增加了67.99%,初始模量降低了51.89%,且纤维表面光滑。     

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。     

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%。     

NMMO处理苎麻织物的X型活性染料染色

以环保型有机溶剂N-甲基氧化吗啉(NMMO)作为溶胀剂,通过轧焙烘预处理,对苎麻织物进行改性,考察了最佳预处理工艺条件和改性后苎麻织物X活性染料的染色性能.结果表明,苎麻织物经40%的NMMO溶液浸渍15min 160℃焙烘2min,然后用X型活性染料染色,其K/S值比未处理苎麻织物提高近一倍,其染色牢度与未处理苎麻织物相近.     

不同脱胶方法对野生苎麻纤维性能的影响

分别采用化学脱胶、微生物脱胶和微生物-化学联合脱胶3种方法对野生苎麻进行脱胶,测试了脱胶纤维的性能,并与人工种植苎麻进行了比较.结果表明在一定条件下,经3种不同方法脱胶后的野生苎麻纤维,残胶率最低为4.08%,最小细度为5.89 dtex,最大强度为5.59 cN/dtex,最大断裂伸长率为4.71%.     

黄麻、洋麻纤维性能研究

为拓展黄麻、洋麻纤维在纺织领域的应用,笔者对精细化处理后的黄、洋麻纤维进行SEM分析和回潮率、力学性能、柔软度、表面摩擦系数及比电阻等性能进行了测试,并将黄、洋麻纤维与苎麻纤维性能进行比较,研究其可纺性。从SEM图可发现黄、洋麻纤维的表面有沟槽,而且其摩擦系数与苎麻相接近,可说明纤维之间有一定的抱合力;黄、洋麻纤维和苎麻纤维的断裂伸长率都在4%~5%之间,而且黄麻纤维的断裂强度比苎麻的高136.48%,洋麻纤维断裂强度比苎麻高70.13%;虽然黄、洋麻纤维的柔软度比苎麻低50%左右,但综上可得:黄、洋麻纤维具有一定的可纺性,说明黄麻、洋麻纤维在纺织领域具有很大的发展潜力。     

N-甲基吗啉-N-氧化物去除苎麻残胶研究

苎麻生物脱胶后的残胶影响其后续纺纱加工.在不损伤纤维素的前提下,采用绿色环保且可回收的N-甲基吗啉-N-氧化物(NMMO)水溶液对苎麻生物脱胶麻的残胶进行处理,考察w(NMMO)、温度、时间和浴比对去除苎麻残胶的影响.结果表明,苎麻在w(NMMO)=50％,70℃,浴比1∶20水浴加热60min条件下,残胶率达到最低(2.28％).     

自捻纱的拉伸力学性能

针对自捻纱断裂强力和断裂伸长率较低的问题,通过对同种原料自捻纺纱线和环锭纺纱线的拉伸力学性能进行对比,讨论了适合自捻纺纱的纤维和必须经过复合才能进行自捻纺纱的纤维以及对纤维配比的要求。与环锭纺纱线相比,羊毛、腈纶、涤纶自捻纱的断裂强力依次降低81.25%、49.33%、31.39%。涤纶、腈纶等纤维能直接采用自捻纺加工方式,而羊毛和苎麻不能直接采用自捻纺纱,必须和其他原料复合自捻。分别对毛/涤纶、麻/涤纶、腈纶/涤纶双组分复合自捻纱进行拉伸力学性能分析,结果表明,要使纱线拉伸性能符合要求,2种原料的组分中涤纶纤维含量需满足：毛/涤纶纱中占60%以上,麻/涤纶纱中占71%以上,但腈纶/涤纶纱的纤维配比不受限制。     

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.     

热处理条件对苎麻织物性能的影响

在干热空气、过热蒸汽和饱和蒸汽热处理条件下,对苎麻织物和涤麻混纺织物的弹性、断裂强度、聚合度、耐磨性等性能变化进行了研究,并探讨了热处理条件对这些性能的影响.     

超临界流体技术在苎麻织物中的应用研究

对影响超临界CO2流体处理苎麻纤维的因素，如温度、压力、时间以及助溶剂进行正交试验，对处理后的苎麻纤维的含杂情况、微结构、机械物理性能和热稳定性等性质作了测试分析。结果表明，超临界CO2流体处理苎麻织物的最佳工艺条件为：工作温度120℃、压力25MPa、时间40min、助溶剂0．1％。该处理可改善苎麻纤维的性能，提高其膨胀性，有利于后续加工，并为其进一步改性打下基础。     

Diammonium phosphate-modified ramie fiber reinforced polylactic acid composite and its performances on interfacial,thermal, and mechanical properties

In this study, the properties of molded ramie fibers reinforced with polylactic acid (PLA) biocomposites were investigated. Before preparation of composites, diammonium phosphate (DAP) was applied to the surface of ramie fibers with and without pretreatments to analyze the interfacial adhesion of ramie–PLA composite. Wettability and adhesion behavior of ramie fibers in the PLA resin were characterized by contact angle (CA) measurements. The surface chemical analysis was performed by Fourier transform infrared spectroscopy (FTIR). The thermal properties were recorded using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The wetting analysis results showed that the introduction of DAP treatment to ramie fibers significantly improved the wetting behavior of ramie in the PLA resin. Similarly, the results of TGA indicated that DAP treatment substantially decreased the degradation temperature of the composites. The result of FTIR was also consistent with the results of wettability, TGA, and DSC for the observed changes of peaks in the transmission spectrum.     

Study on the Pre-Treatment,Physical and Chemical Properties of Ramie Fibers Reinforced Poly (Lactic Acid) (PLA) Biocomposite

The comparative advantage of using vegetable fibers as reinforcement (fillers) attracted manufacturing industries over conventional composites. Natural fibers are purely green features that can easily decompose in a normal way to water and CO₂ when encountered with moisture during their disposal. In this research, the effect of pre-treatment and properties of ramie fibers reinforced polylactic acid (PLA) composite were studied. Before the composite preparation, ramie fibers were soaked in a solution of alkali (sodium hydroxide) and silane coupling agent to provide better compatibility between ramie fibers and PLA interface. Additionally, a design containing nine samples was conducted to study the effect of temperature, fiber volume ratio, molding pressure and time on composite fabrication. From the results, optimum processing parameters were identified based on the tensile, bending and impact strengths improvement from various tested samples. Furthermore, this study highlights the degradation process and properties of ramie fibers reinforced PLA composites by underground burial experimental procedures.     

Degumming of ramie bast fibers by Ca2+-activated composite enzyme

In recent years, special attention has been paid to the application of biotechnology in the textile industry. In this study, composite enzyme (contained pectatelyase/hemicellulase/laccase) was employed to degum the ramie bast successfully. Interestingly, the activities of enzymes were enhanced by promotion of Ca²⁺ activated remarkably. The test of degummed ramie fiber performance demonstrated that fiber fineness, breaking strength, whiteness, and residual gum of fibers have greatly improved. Further, the structure and morphous of the fibers before and after degumming was examined and analyzed. The results showed that the gum, hemicellulose, and lignin were removed effectively and treated fibers had the typical cellulose I structure suitable for direct textile and other applications. These outcomes suggested that Ca²⁺-activated composite enzyme could degum the gum of ramie bast effectively, which provided a method to improve the quality of ramie fibers and a theoretical basis for flax degumming technique on an environmentally-friendly basis.     

应用1-辛烯涂层与常压等离子体处理的苎麻纤维疏水性能改性

为提高苎麻纤维与聚丙烯（PP）之间的界面相容性,采用1-辛烯涂层结合常压等离子体射流(APPJ)技术对苎麻纤维表面进行疏水性改性,并研究了改变 2 种方法的处理顺序对改性效果的影响。通过改性前后苎麻纤维的表面形态、润湿性、表面化学成分及苎麻/PP界面剪切强度的变化分析改性效果。实验结果显示,经等离子体处理后再进行1-辛烯涂层处理的苎麻纤维表面的C元素含量提高最明显,且该组苎麻纤维/PP界面剪切强度与未处理组相比提高了近40.0%,而改变处理顺序后得到的苎麻纤维与PP的界面剪切强度仅提高了18.2%。     

N-甲基吗啉-N-氧化物基超细炭黑的制备

为解决水性颜料色浆对Lyocell纤维纺丝液造成的凝固问题,制备了NMMO基超细炭黑色浆,利用其对Lyocell纤维进行原液着色。针对Lyocell纤维原液着色用超细炭黑的制备展开研究,探讨了分散剂的结构及用量,炭黑质量分数,水和NMMO组成混合溶剂中水的质量分数,超声波处理功率及时间对NMMO基超细炭黑的粒径、粒度分布及分散稳定性的影响。结果表明,以实验室自制的分散剂SP制备的NMMO基超细炭黑具有最小的粒径及优良的分散稳定性,与纺丝液相容性最好。通过正交试验优化得到NMMO基超细炭黑的制备工艺：分散剂对炭黑的质量分数2为20 %,炭黑对体系的质量分数为10 %,超声波处理时间为20 min,功率为800 W。