基于纳米石墨微片制备的聚醚醚酮复合材料及其摩擦学性能研究

发布时间：2018-06-02 23:28

本文选题：聚醚醚酮 + 纳米石墨微片　；参考：《吉林大学》2015年硕士论文

【摘要】：聚醚醚酮(PEEK)树脂具备极其优异的综合性能，且适用于传统热塑性塑料的成型加工工艺，使其成为航空航天、能源化工、交通运输、食品加工、医疗卫生等领域的理想材料。聚醚醚酮作为耐磨材料，能在较广的温度、载荷、速度和接触界面粗糙度范围内保持优良的耐磨损性能，在聚合物摩擦材料领域显示出非常广阔的应用前景。但是在干摩擦条件下，PEEK的摩擦系数较高，限制了PEEK在摩擦领域的应用。纳米石墨微片(GNS)作为一种典型的碳系材料，不但继承了石墨低廉的价格、优良的润滑特性等优点，还具有极高的径厚比(直径/厚度比)和超大的比表面积，使其成为了制备耐磨复合材料的理想填料。本论文以聚醚醚酮树脂为基体材料，，纳米石墨微片为主要填料，围绕高性能聚醚醚酮基耐磨材料的制备展开一系列工作。我们利用与聚醚醚酮综合性能匹配的聚醚砜(PES)对GNS进行表面修饰，得到聚醚砜包覆的纳米石墨微片(GNS@PES)，然后利用传统的熔融共混的方式制备PEEK/GNS@PES和PEEK/GNS两个系列复合材料，并对不同含量GNS填料的两个系列复合材料的性能等进行了综合的分析和对比。研究结果表明，GNS填料的引入提高了材料的力学性能、热稳定性、尺寸稳定性以及摩擦磨损性能。由于填充材料表面的PES在GNS与PEEK树脂之间形成了一个界面层，这个界面层不但能够改善GNS在PEEK基体中的分散性，而且还能提高GNS与PEEK基体的界面作用力，这就使得PEEK/GNS@PES复合材料不论是力学性能还是摩擦磨损性能都要优于PEEK/GNS复合材料。对于聚合物基摩擦材料而言，良好的力学性能不但有助于提高摩擦性能，而且还能拓宽摩擦材料的应用领域。碳纤维(CF)是一种性能卓越的增强材料，与聚合物复合后不但能够赋予复合材料极高的强度、模量，还可以提高复合材料摩擦磨损性能。基于此我们将碳纤维引入到PEEK/GNS@PES体系中，制备了PEEK/GNS@PES/CF三元复合材料。测试结果表明，与仅添加GNS@PES相比，碳纤维的引入显著提高了复合材料的机械性能和摩擦磨损性能。聚四氟乙烯(PTFE)具有特殊的螺旋形构型，分子间易于滑移，同时氟原子构成的外壳使得PTFE分子轮廓光滑，这既保证了PTFE能在滑动过程中展现出优异的摩擦学性能，又能在摩擦接触界面处形成稳定且均匀的转移膜，使其具有极低的摩擦系数。为了进一步降低聚醚醚酮基复合材料的摩擦系数，拓宽其应用领域，我们固定碳纤维和GNS@PES的含量都为10wt%，将PTFE引入制备PEEK/GNS@PES/CF/PTFE四元复合材料。研究结果表明，四元复合材料的摩擦系数仅为0.254，PTFE的引入显著降低了复合材料的摩擦系数。
[Abstract]:Polyether ether ketone (PEEK) resin has excellent comprehensive properties and is suitable for traditional thermoplastic molding process, which makes it an ideal material in aerospace, energy and chemical industry, transportation, food processing, medical treatment and so on. Polyether ether ketone, as a wear-resistant material, can maintain excellent wear resistance in a wide range of temperature, load, speed and contact interface roughness. However, the friction coefficient of peek is higher under dry friction condition, which limits the application of PEEK in friction field. As a typical carbon system material, nano-graphite microchip GNS not only inherits the advantages of low price of graphite and excellent lubricating properties, but also has extremely high diameter to thickness ratio (diameter / thickness ratio) and large specific surface area. It is an ideal filler for the preparation of wear-resistant composite materials. In this thesis, polyether ether ketone resin was used as matrix material and nano-graphite microchip was used as main filler to prepare high performance polyether ketone based wear resistant material. GNS was modified by polyethersulfone (PES), which was matched with polyether ether ketone (PES), and then PEEK/GNS@PES and PEEK/GNS composites were prepared by traditional melt blending method. The properties of two series composites with different GNS fillers were analyzed and compared. The results show that the mechanical properties, thermal stability, dimensional stability and friction and wear properties are improved with the introduction of GNS filler. Due to the formation of an interfacial layer between GNS and PEEK resin by PES on the surface of the filler material, this interfacial layer can not only improve the dispersion of GNS in PEEK matrix, but also enhance the interfacial force between GNS and PEEK matrix. Therefore, the mechanical properties and friction and wear properties of PEEK/GNS@PES composites are superior to those of PEEK/GNS composites. For polymer based friction materials, good mechanical properties can not only improve the friction properties, but also broaden the application of friction materials. Carbon fiber reinforced carbon fiber (CFC) is a kind of reinforced material with excellent properties. Composite with polymer can not only endow the composites with extremely high strength and modulus, but also improve the friction and wear properties of composites. Based on this, we introduce carbon fiber into PEEK/GNS@PES system and prepare PEEK/GNS@PES/CF ternary composites. The results show that the addition of carbon fiber can improve the mechanical properties and friction and wear properties of the composites compared with only adding GNS@PES. PTFE (PTFE) has a special spiral configuration, and it is easy to slip between molecules. Meanwhile, the shell made of fluorine atoms makes the PTFE molecule silhouette smooth, which ensures that PTFE can exhibit excellent tribological properties during the sliding process. A stable and uniform transfer film can be formed at the frictional contact interface, which makes it have a very low friction coefficient. In order to further reduce the friction coefficient of polyether ether ketone matrix composites and broaden their application fields, we fixed the content of carbon fiber and GNS@PES at 10 wts. we introduced PTFE into PEEK/GNS@PES/CF/PTFE quaternary composites. The results show that the friction coefficient of the quaternion composite is only 0.254% PTFE, and the friction coefficient of the composite is significantly reduced by the introduction of PTFE.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332

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