疏水性处理改善苎麻纤维与聚丙烯树脂界面性能的研究

发布时间：2018-03-28 00:37

本文选题：常压等离子体　切入点：苎麻纤维　出处：《东华大学》2015年硕士论文

【摘要】：天然纤维复合材料是一种新型绿色环保材料，由于其密度低、隔音效果好、比强度高、可回收、价格低廉、人体亲和性好等优点，被广泛应用于汽车工业、建筑工业、日用消费品等领域。天然纤维由于有着来源丰富，价格低廉，并且可再生自然降解等优异性能，被广泛应用于纤维增强复合材料中。苎麻纤维是一种纺织工业常用的天然纤维，它非常坚韧，比强度大且延伸度小，并且不易受霉菌腐蚀和虫蛀，是天然纤维增强复合材料的理想增强纤维。热塑性树脂是指这种树脂在不起化学反应的情况下具有可重复受热软化、冷却硬化的性能。这一特性使热塑性树脂可以循环应用，使它越来越受到环境可持续发展材料研究工作者的青睐。聚丙烯树脂是通用树脂中最轻的树脂，它无味、无毒并且质轻，是一种机械性能和耐热性能良好的热塑性树脂，并且化学稳定性好，耐酸碱和有机溶剂，几乎不吸水，这些性能使聚丙烯树脂成为天然纤维复合材料中优异的基质成分。由于在纤维增强复合材料中，复合材料的性能不仅取决于增强材料和基质材料的性能，而且取决于增强材料和基质材料组分间的界面相容性，并且后者对纤维增强复合材料的性能有很大的影响。苎麻纤维良好的吸湿性不仅导致了纤维与聚丙烯树脂之间较差的界面粘结性能，而且吸湿溶胀会破坏复合材料内的纤维与树脂之间的粘结，从而导致复合材料性能的失效。常压等离子处理技术是一种新型有效的表面改性技术。相对于需要真空干燥条件的等离子体表面改性技术而言，常压等离子处理技术具有可持续性操作、成本低廉、处理时间短和灵活度高等优势。最重要的是常压等离子体技术还能处理含液材料，这样极大的扩展了等离子技术的应用范围。由于在纺织品的加工工序中，常常要进行湿处理，并且许多纤维尤其是天然纤维一般都具有较好的吸湿性，同时纺织车间所需的高湿度，都使纺织品在加工流水线上具有较高的含水率。常压等离子技术的出现使等离子体处理能应用到纺织工业当中去。常压等离子技术可以有效的处理苎麻纤维表面，提高苎麻纤维表明粗糙度，改善纤维表面极性。但是由于聚丙烯树脂是一种几乎不吸水的热塑性树脂，提高苎麻纤维表面的亲水性可能会导致苎麻纤维和聚丙烯树脂之间粘结性能的下降。因此为了提高纤维与树脂之间的粘结性能，需要一种切实有效的表面改性方法去提高苎麻纤维表面的粗糙程度，并且降低苎麻纤维的亲水性，从而改善苎麻纤维与聚丙烯树脂之间的粘结性能，提高苎麻纤维复合材料的机械性能。本课题利用常压等离子体表面改性技术结合醇类预处理对苎麻纤维表面进行疏水改性。通过热熔的方法将聚丙烯树脂与苎麻纤维制成微复合材料样品，采用微粒脱落的方法测得苎麻纤维与聚丙烯树脂之间的界面剪切强度来表征界面粘结性能。并对纤维表面进行各项测试，从而表征苎麻纤维表面性能的改善。首先对苎麻纤维进行表面预处理，本课题选取了3种不同的醇类，乙醇，异丙醇，正丁醇。然后采用常压等离子体射流对苎麻纤维进行表面改性。频率为13.56MHz，放电功率是40W。气流采用高纯度的氦气(99.99%)，气流流速为20L/min.工作高度为2mm,处理时间在8-24s范围内。然后采用扫描电子显微镜观察苎麻纤维表面形态，X射线光电子能谱分析苎麻纤维表面化学组分，静态接触角表征苎麻纤维表面化学能。然后制备微纤维复合材料样品，通过微粒脱落的方法测得苎麻纤维与聚丙烯树脂之间的界面剪切强度。扫描电子显微镜（SEM）显示在醇类预处理常压等离子体处理之后，苎麻纤维表面粗糙度增加，这有利于苎麻纤维表面与聚丙烯树脂之间的机械锁结；但随着常压等离子体处理时间的增加，大量的缺陷开始出现致使苎麻纤维基体的机械性能受到损伤，导致了复合材料性能的下降。X射线光电子能谱分析（XPS）显示，在经过处理之后，苎麻纤维表面的化学组分发生了明显的变化，疏水的C-C基团在处理后有了明显的增加。静态接触角结果显示处理之后，苎麻纤维表面接触角都有所增大，接近于疏水。这样既有利于改善苎麻纤维表面与聚丙烯树脂之间的粘结，又有利于减少水分的吸收，减少复合材料界面粘结的损伤。苎麻纤维与聚丙烯树脂之间界面剪切强度的测量显示在醇类预处理常压等离子体处理后，界面剪切强度增加；但随着常压等离子体处理时间的延长，界面剪切强度会有所下降。相对与其他醇类预处理，采用异丙醇预处理结合常压等离子体处理的苎麻纤维表面粗糙程度最大，，表面亲水性官能团最少，从而拥有最强的界面剪切强度。相对于潮湿环境，在干燥环境下，采用乙醇预处理结合常压等离子体处理的苎麻纤维表面粗糙程度大，表面疏水性基团多，从而具有更好的界面剪切强度。
[Abstract]:Natural fiber composite material is a new green environmental protection material. Because of its low density, sound insulation effect, high specific strength, recyclability, low price and good affinity, it is widely used in automotive industry, construction industry, consumer goods and other fields.
Because of its rich source, low price of natural fiber, and renewable natural degradation and other excellent properties, is widely used in fiber reinforced composite material. The ramie fiber is a kind of natural fiber textile industry commonly used, it is very tough, high strength and elongation, and not susceptible to corrosion and mildew and insects, is the natural fiber reinforced composite material ideal reinforced fiber.
Thermoplastic resin refers to the resin in the chemical reaction under the condition of having repeated heating and softening, cooling performance of hardening. These properties make the thermal cycling plastic resin can make it more and more environmentally sustainable development of material research workers of all ages. Polypropylene resin is the most common resin, resin light it is tasteless, non-toxic and light, is a kind of mechanical performance and good heat resistance of thermoplastic resin, and good chemical stability, acid and alkali and organic solvents, almost no water absorption, these properties make the polypropylene resin become excellent matrix components of natural fiber composites.
Because of the fiber reinforced composites, the properties of the composites depends not only on the performance of reinforced material and matrix material, but also depends on the reinforcement and the matrix material components of the interface compatibility between reinforced and the latter has great influence on the performance of composite material of fiber. The hygroscopicity of ramie fiber is good not only leads to interfacial bonding poor performance between fiber and polypropylene resin, and hygroscopic swelling will destroy the bond between fiber and resin in composite material, resulting in the failure of the properties of the composite materials.
Atmospheric pressure plasma processing technology is a new and effective surface modification technology. Compared with the vacuum drying conditions of plasma surface modification technology, atmospheric plasma processing technology is sustainable operation, low cost, short processing time and high flexibility advantages. The most important is the treatment of atmospheric pressure plasma technology can containing liquid material, so great the expansion of the scope of application of plasma technology in textile processing. Because of often wet processing, and especially many fiber is natural fiber generally has good moisture absorption, high humidity and textile workshop required, the water content is high in textile processing lines on the rate of atmospheric pressure plasma. The technology of plasma treatment can be applied to the textile industry.
Atmospheric pressure plasma processing technology can effectively improve the surface of ramie fiber and ramie fiber showed that the fiber surface roughness, improve the polarity. But because the polypropylene resin is an almost non absorbent thermoplastic resin, improve the hydrophilicity of ramie fiber surface may lead to reduction of bond performance between ramie fiber and polypropylene resin. In order to improve the bond properties between fiber and resin, the need for a practical and effective method of surface modification to improve the surface roughness of ramie fiber, and reduce the hydrophilicity of ramie fiber, so as to improve the adhesive properties between ramie fiber and polypropylene resin, improve the mechanical properties of ramie fiber composites. The atmospheric pressure plasma surface modification technology alcohol pretreatment hydrophobic modification of ramie fiber surface using this topic. Through the hot melt method of polypropylene resin and ramie The interfacial shear strength between ramie fiber and polypropylene resin was measured by particle shedding to characterize the interfacial bonding properties. The surface properties of ramie fiber were tested to characterize the surface properties of ramie fiber.
The ramie fiber surface pretreatment, this paper selects 3 kinds of alcohols, ethanol, isopropanol, butanol. Then the surface modification of ramie fiber by atmospheric pressure plasma jet. The frequency is 13.56MHz, the discharge power is 40W. with high purity helium gas (99.99%), air flow velocity is 20L/min. working height for 2mm, the processing time in the range of 8-24s. Scanning electron microscope and the observation of surface morphology of ramie fiber, X ray photoelectron spectroscopy analysis of ramie fiber surface chemical composition, the static contact angle, surface chemical characterization of ramie fiber. Then the preparation of micro fiber composite samples, through the method of measuring the interfacial shear strength of particles falling between ramie fiber and polypropylene resin.
Scanning electron microscopy (SEM) showed that after alcohol pretreatment atmospheric plasma processing of ramie fiber, the surface roughness increases, which is conducive to the surface between the ramie fiber and polypropylene resin mechanical lock; but with the increasing of atmospheric pressure plasma processing time, a large number of defects appeared in mechanical properties of ramie fiber matrix resulting in damage caused by.X ray photoelectron spectrum analysis of the properties of the composite materials (XPS) showed that after the treatment, the ramie fiber surface chemical composition changed obviously, the hydrophobic C-C group has increased significantly after the treatment. The static contact angle showed that after processing, the ramie fiber surface contact angle increase. Close to the hydrophobic. This is conducive to the improvement of adhesion between the surface and the polypropylene resin of ramie fiber, and to reduce the absorption of moisture, reduce the composite material. The material interface bond damage. Measuring between ramie fiber and polypropylene resin interfacial shear strength in alcohol pretreatment after atmospheric pressure plasma treatment, increase the interfacial shear strength; but with the extension of atmospheric pressure plasma treatment time, the interfacial shear strength will decrease. Compared with other alcohol pretreatment, using isopropanol pretreatment combined with atmospheric plasma treatment the ramie fiber surface roughness, surface hydrophilic functional groups at least, the interfacial shear strength which has the strongest. Compared to the humid environment, in a dry environment, using ethanol pretreatment combined with ramie fiber surface roughness of atmospheric pressure plasma treatment, surface hydrophobic groups, interfacial shear strength and is the better.

【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332

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