【作者】 刘艳春；

【导师】 陆大年；

【作者基本信息】 东华大学 ， 纺织化学与染整工程， 2005， 博士

【摘要】 腈纶是世界主要合成纤维之一，它手感柔软，色泽鲜艳，强度和弹性都比较好。但由于它是疏水性纤维，吸湿性差，易起静电，从而限制了它的进一步发展。适当的物理和化学方法可以改善抗静电性能，但存在不同程度的环境污染问题。低温等离子体技术作为一种环境友好的新技术，节水，节能，无污染，具有显著的经济及环保效应。本文采用低温等离子体技术对腈纶进行表面改性，所采用的等离子体处理方法主要有真空辉光放电等离子体表面处理、常压介质阻挡放电等离子体表面处理及常压介质阻挡放电等离子体接枝处理。试验中，通过改变等离子体处理气氛、时间、压强及功率条件，研究了有关处理参数的变化对腈纶抗静电性能的影响。氧、氮真空辉光放电等离子体表面处理能较有效地改善腈纶的抗静电性能。抗静电性能随处理功率的增加而增加。当处理压强低于25Pa时，增加压强，纤维的抗静电性能上升，但继续增加压强，抗静电性能反而下降。短时间内，处理纤维的抗静电性能随处理时间的增加而增加，进一步延长处理时间并不能继续提高纤维的抗静电性能。氩气、氩气／氮气常压介质阻挡放电等离子体表面处理也能使腈纶的抗静电性能得到明显提高。两种气氛(氩气、氩气／氮气)常压介质阻挡放电等离子体表面处理的最优工艺条件都是：处理电压7000V，时间1分钟，频率19kHz。常压介质阻挡放电等离子体表面处理对腈纶的表面改性可以达到氧、氮真空辉光放电等离子体的改性效果。腈纶经氩气常压介质阻挡放电等离子体接枝处理后，由于季铵盐基团的引入，腈纶的抗静电性能得到明显提高。经等离子体接枝处理后，腈纶的透湿性能明显提高，透气性能略有降低。本文采用扫描电镜(SEM)、氮吸附比表面积测试法(BET)、X射线光电子能谱(XPS)、红外测试等现代分析技术，对不同处理条件下的腈纶纤维进行测试，研究了等离子体处理后纤维表面物理结构和化学性能的变化。SEM、BET测试结果表明，等离子体表面处理对腈纶纤维表面有明显的刻蚀作用，可使纤维表面变得粗糙，比表面积增大。XPS测试结果表明，等离子体表面处理可使腈纶纤维表面含氧量明显提高，在纤维表面引入了大量的酰胺基和羧基等亲水基团。这些亲水基团能吸收空气中的水分，纤维吸附水分的离子化以及水分诱导周围不纯物质的离子化，使纤维电导率显著增加，比电阻下降，这是腈纶抗静电性能得到改善的主要原因。红外测试结果表明，腈纶经氩气常压介质阻挡放电等离子体接枝处理后，表面引入了季铵盐基团，使腈纶的抗静电性能得到明显提高。X射线光电子能谱(XPS)分析表明腈纶纤维经等离子体表面处理后，纤维表面发生化学改性，酰胺基和羧基等亲水性基团被引入到纤维表面。酸性染料TECTILON Yellow 4R含有磺酸基，能与纤维表面产生的酰胺基发生吸附作用，而阳离子染料能与纤维表面产生的羧基发生吸附，两种染料吸附量的变化可用来反映等离子体处理在腈纶纤维表面引入的酰胺基和羧基数量的变化情况。染色实验具有灵敏性高、重现性好等特点，因此本文主要采用染色法结合其它方法来评价腈纶纤维表面改性的效果。染色结果表明，经真空辉光放电等离子处理后，腈纶纤维上两种染料的吸附量与K／S值均有较为明显的提高，表明等离子体处理后大量的酰胺基和羧基被引入到纤维表面。低温等离子体表面处理普遍具有时效性问题，因此本文也对腈纶等离子体改性的时效性问题进行了研究。研究发现，腈纶等离子体表面处理具有时效性问题，随着放置时间的延长，改性后的良好性能会逐渐退化。处理效果随放置时间延长衰退的主要原因是由于材料表面极性基团的转移和重排所致，与分子链运动的难易程度密切相关，在很大程度上取决于纤维表面的结晶程度及所放置的环境(包括介质和温度)。结晶度高的样品改性后得到的亲水性能丧失较慢；放置在亲水环境中的样品没有丧失其得到的亲水特性，而放置在疏水环境中的样品却渐渐回复了其原有的疏水特性；放置在液氮中的样品其得到的亲水特性没有丧失，放置在室温及90℃高温下的样品会部分丧失其得到的亲水特性。等离子体接枝改性的效果比较稳定，改性样品的亲水性能并不随放置时间的延长而衰减。综上所述，等离子体处理作为一种清洁生产新技术，应用到腈纶的表面改性中，不但能达到抗静电改性的目的，还能节省能源和化学品，减少生产过程中废物的排放量和毒性，推动环境保护和清洁生产。更多还原

【Abstract】 Acrylic fiber is one of leading synthetic fibers due to its high strength, goodelasticity and excellent dyeability. However, the inherent poor absorbency,accompanied by the high build-up of static charges limits its further development.These shortcomings might be alleviated by chemical and physical modificationof the materials. Although chemical modification of the fibers has been somewhatsuccessful in improving hydrophilic and anti-static properties, there areenvironmental concerns related to the disposal of chemicals after treatment. Plasmatreatment, as a clean, dry and environmental friendly physical technique, opens up anew possibility in this field.Acrylic fibers were treated with three different plasma treatment methods, i.e.glow discharge plasma treatment, dielectric barrier discharge plasma treatment andplasma graft treatment. The wettability and anti-static ability of treated acrylic fiberswere researched firstly under different gas atmosphere, processing time, cabinetpressure and discharge power conditions.The oxygen or nitrogen glow discharge plasma treatment can improve surfacewettability and anti-static ability of acrylic fibers. A better anti-static property wasobtained with a longer plasma treating. But the excessive long treatment brought areverse result. When the power increased, the anti-static property increased. Theanti-static property was best around 25Pa, the lower or higher pressure also resultedanti-static property decreasing.The argon or argon/nitrogen dielectric barrier discharge plasma treatment canalso improve the anti-static property of acrylic fibers. The optimum processingcondition was as follows: the voltage 7000V, the frequency 19kHz, the processingtime lmin.Scanning electron microscopy (SEM) photographs and specific surface area(BET) analysis showed that plasma treatment causes the increase of surfaceroughness and the specific surface area.X-ray photoelectron spectroscopy (XPS) analyses revealed that plasma treatment introduces an amount of amide and carboxyl groups on the fiber surface.These polar groups will incorporate with moisture through hydrogen bonding andhelp moisture penetration and binding on the fiber surface. Under the action ofwater molecular, these polar groups will also generate ionization and lead to astructural layer of conduct electricity on the fiber surface, which enhances theelectrostatic dissipation. Therefore, the anti-static property of acrylic fiber increasedafter plasma treatment.The plasma graft treatment can introduce the quaternary ammonium saltgroups onto the fiber surface, so the anti-static property of acrylic fiber increaseddrastically. After plasma graft treatment, the moisture permeability increased andthe breathability decrease lightly.Dyeing was used to evaluate the result of plasma modification of acrylic fibers.Plasma treatment introduced the amide and carboxyl groups onto the fiber surface.The amide groups can incorporate with acid dye and the carboxyl groups canincorporate with cation dye. Therefore, the uptake of two dyes can be used to reflectthe change of the introduced amide and carboxyl groups.The dyeing results show that the uptake and K/S value of two dyes increasedobviously after glow discharge plasma treatment, indicating that an amount ofamide and carboxyl groups have been introduced on the fiber surface. Theincreasing time resulted an increase of the uptake and K/S value at first. But alonger processing time resulted a decrease of dye behavior. When the dischargevoltage increased, the uptake and the K/S value were increased too. An increasingpressure induced the increase of dyeing behaviors, but extremely higher pressurebrought opposite result.Plasma treatment is a very useful method for modifying the surface propertiesof polymer materials. However, the modification of the surface is not permanent.Often the hydrophilicity obtained is lost with time. In this paper, we also investigatethe ageing behavior of the plasma treated acrylic fibers.The results showed that the surfaces of glow discharge plasma treatment showdifferent ageing process of the modification. The ageing process can be mainly ascribed to the molecular movement of polymer chains, leading to the reorientationof polar groups. The crystallinity of the treated samples has a critical influence onthe degree of ageing since the process involves the mobility of polymer chains.Increasing crystallinity reduces the rearrangement of polar groups and thus preventsthe ageing process of the modification. In addition, the environment andtemperature that the surface is stored also play an important role in the ageingprocess. A hydrophobic environment promotes faster recovery of the originalproperties. A hydrophilic environment prevents the surface from losing the polarcharacter obtained from the plasma treatment. As the temperature is high, thesample exhibits a significant ageing process since the mobility of polymer chains ispromoted. At extremely low temperature (in liquid nitrogen), the sample is expectedto maintain its hydrophilic character after plasma treatment since there is nodiffusion migration of polar groups.There is no obviously ageing behavior for plasma graft treated surfaces. Thisresult indicates that the effect of plasma graft is more stable than that of plasmasurface processing.It can be summarized that plasma treatment can enhance the wettability andanti-static ability of acrylic fibers. The application of plasma technology can greatlyreduce the consumption of water, energy and chemicals. At the same time, less toxicsubstance or pollutions will be released during process. So plasma technology offersthe potential for simultaneous economic and environmental gains in the textileindustries.更多还原