聚醚醚酮及其复合材料摩擦学研究近况

近年来,国内外的摩擦学研究者对聚醚醚酮（ＰＥＥＫ）及其复合材料的摩擦学行为进行了广泛的研究,目的是在保持ＰＥＥＫ其它优越性能的基础上,使其减摩和抗摩性能有所提高,以扩展这一新型工程塑料的应用领域。本文对ＰＥＥＫ及其复合材料的摩擦学研究近况进行了综述。     

CF／PEEK界面微观结构的研究

本文研究了聚醚醚酮(PEEK)在碳纤维表面形成的界面横晶层的微观结构。结果表明横晶具有与周围球晶相同的晶片结构,但横晶中晶片及其聚集体沿垂直于纤维轴向的方向取向排列。横晶的形成是由于纤维表面成核点很多,晶体只能沿一方向择优生长的结果。     

CF/PEEK复合材料界面层结构与性能关系研究

本文根据聚醚醚酮(PEEK)在碳纤维表面形式的横晶层的结构特征分析,建立了CF/FEEK复合材料界面层微观力学性能的理论方程,计算了界面层的杨氏模量.通过超声浸渍法测量复合材料的力学性能验证了计算结果,证明所进行的分析合理.计算结果表明,PEEK界面横晶层在垂直于纤维方向的杨氏模量E_r随PEEK结晶度的增大,或随横晶中PEEK晶片长度的增大而增大,并随晶片厚度的增大而减小.该界面层的上述模量值始终高于界面层附近球晶的模量值E_s,两者之间的比值E_T/E_s;依赖于横晶及球晶中的晶片长度b、厚度c和宽度a.由于界面层的模量高于非界面层的模量,当复合材料中纤维表面形成横晶时,复合材料将有较高的刚性.     

仿生多孔润滑耐磨CF/PTFE/PEEK复合材料的设计及其摩擦学性能

采用模压-滤取和高温真空熔渍工艺制备了自身发汗式润滑耐磨多孔CF/PTFE/PEEK复合材料。考察了造孔剂(NaCl)、PTFE的含量及炭纤维层间间距对多孔PEEK复合材料结构和摩擦学性能的影响。结果表明,当PTFE含量为20%(质量分数,下同)、NaCl为30%、炭纤维层间间距为0.4mm所得多孔CF/PTFE/PEEK复合材料摩擦因数和磨损率最低,200N下摩擦因数、磨损率分别为0.0192,3.47×10-16 m3/Nm,较经典CF/PEEK复合材料摩擦因数降低了9倍,耐磨性提高了25倍。原因在于复合材料中PTFE能形成连续的转移膜,降低了材料摩擦因数;NaCl形成的多孔结构能储存住一定润滑油脂,摩擦过程中在载荷和温度的作用下能形成稳定润滑油膜,明显降低了材料磨损量;炭纤维布起到支撑骨架作用,并协同PTFE,NaCl提高多孔PEEK复合材料摩擦磨损性能。     

碳纳米管改性CF/PEEK复合材料的力学与电磁屏蔽性能

为了制备兼具优异力学性能和电磁干扰屏蔽效能的结构功能一体化耐高温热塑性复合材料,对添加不同组分碳纳米管(CNT)的连续碳纤维增强聚醚醚酮复合材料(CF-CNT/PEEK)的力学性能、电导率以及电磁干扰屏蔽效能(EMI SE)进行了研究。考察用上浆后的CNT (SCNT)作为导电填料制备的SCF-SCNT/PEEK层合板力学性能、界面形貌和屏蔽效能,并与不进行表面修饰、仅活化的CNT (ACNT)的效果做对比实验。结果表明,适量的CNT会使CF/PEEK层合板的力学性能、电导率和EMI SE得到提高;SCNT比ACNT更容易在PEEK中均匀分散,且与SCF和PEEK的结合更好。所有样品中,仅添加1wt%SCNT的SCF-SCNT/PEEK层合板与不添加CNT的层合板相比,拉伸强度提高了20.8%,达到778 MPa;弯曲强度提高了25.9%,达到1 684 MPa;电导率提升5倍,达到0.15 S/cm;电磁干扰屏蔽效能提升69.76%,平均值达到34.97 dB。     

玻璃纤维增强聚醚醚酮复合材料在水润滑下的摩擦学性能

利用球盘式摩擦磨损试验机考察了玻璃纤维(GF)增强聚醚醚酮(PEEK)复合材料在干摩擦和水润滑条件下的摩擦磨损性能,并探讨了其磨损机理。结果表明:在干摩擦和水润滑条件下,PEEK和GF/PEEK的摩擦因数和磨损率均随载荷和对磨时间的增加逐渐增大并趋于稳定,GF的加入可以显著降低GF/PEEK复合材料的摩擦因数和磨损率;在水润滑条件下,PEEK和GF/PEEK的摩擦因数和磨损率比干摩擦下显著降低。干摩擦下,PEEK以黏着磨损和磨粒磨损的混合磨损形式为主,水润滑条件下,磨损方式主要是以轻微的黏着磨损为主;干摩擦下,GF/PEEK磨损表面有大量的微观断裂裂纹和破碎,以磨粒磨损和疲劳磨损为主,水润滑条件下,磨损表面仅有微观切削的痕迹,磨损方式以轻微磨粒磨损为主。由于水的冷却和润滑作用,使得复合材料向对偶钢球的黏着转移明显减弱,同时阻止了对偶钢球上的Fe向复合材料磨损表面转移,从而减轻摩擦、降低摩擦表面温升,显著改善复合材料的摩擦磨损性能。     

聚醚醚酮及其复合材料摩擦学研究近况

近年来 ,国内外的摩擦学研究者对聚醚醚酮 (PEEK)及其复合材料的摩擦学行为进行了广泛的研究 ,目的是在保持 PEEK其它优越性能的基础上 ,使其减摩和抗磨性能有所提高 ,以扩展这一新型工程塑料的应用领域。本文对 PEEK及其复合材料的摩擦学研究近况进行了综述。     

聚醚醚酮复合材料的摩擦学研究

采用模压方法制备了多元PEEK耐磨汽车材料。用环-块磨损实验机对复合材料进行了磨损试验,用SEM方法对复合材料的磨损表面进行了观察和分析,并利用DSC、FT-IR和SEM分析方法对复合材料的磨屑进行了研究,在上述基础上进行了复合材料的磨损机理探讨。结果表明,与PEEK相比,PEEK复合材料具有优良的摩擦学性能;PEEK复合材料磨屑的熔点比相应模压材料有所降低,且磨屑的熔限比相应的模压材料有所加宽;随着Ekonol含量的增加,复合材料的磨损机理发生了由粘着磨损为主向疲劳磨损为主的转变。     

碳纤维和二硫化钼混杂增强尼龙复合材料的摩擦学性能研究

以注塑成型法制备MoS₂和碳纤维混杂增强尼龙1010复合材料,采用MM-200型磨损试验机考察复合材料摩擦磨损性能。研究结果表明:在干摩擦条件下,MoS₂和碳纤维混杂可显著改善尼龙复合材料摩擦学性能,较小载荷下复合材料磨损以轻微磨粒磨损和疲劳磨损为主,较高载荷下复合材料则以热疲劳断裂剥落磨损为主。摩擦过程中MoS₂和对偶铁发生摩擦化学反应,生成和对偶底材具有较强结合能力的硫化亚铁和硫酸铁等,同时部分被氧化生成MoO₃。     

聚醚醚酮摩擦学性能改性及其应用研究进展

本文综述了聚醚醚酮(Polyetheretherketone,PEEK)的特性及其应用,重点探讨了PEEK复合改性中的无机填料填充、纤维增强、聚合物共混及表面改性四个方面对PEEK复合材料性能的影响,简述了PEEK复合材料在航空航天领域、汽车工业及涂料工业中的应用研究进展,并指出PEEK改性过程中纳米材料的团聚以及无机有机物的相容性仍是目前亟待解决的重要问题,寻求更多的增强体和简便复合工艺以实现材料更优性价比是今后的研究重点。     

Electron-beam irradiation effects on mechanical properties of PEEK/CF composite

Carbon fibre-reinforced composite (PEEK/CF) using polyarylether-ether-ketone (PEEK) as a matrix material was prepared and electron-beam irradiation effects on the mechanical properties at low and high temperatures were studied. The flexural strength and modulus of the unirradiated PEEK/CF were almost the same as those of carbon fibre-reinforced composites with epoxide resin. The mechanical properties at room temperature were little affected by irradiation up to 180 MGy, but in the test at 77 K the strength of the specimens irradiated over 100 MGy were slightly decreased. The mechanical properties of the unirradiated specimen decreased with increasing testing temperature, but the high-temperature properties were improved by irradiation, i.e. the strength measured at 413 K for the specimen irradiated with 120 MGy almost reached the value for the unirradiated specimen measured at room temperature. It was apparent from the viscoelastic measurement that the improvement of mechanical properties at high temperature resulted from the high-temperature shift of the glass transition of the matrix PEEK caused by radiation-induced cross-linking.     

Thermal aging effects on mechanical and tribological performance of PEEK and short fiber reinforced PEEK composites

The effects of thermal aging on the properties of unfilled and random oriented short fiber reinforced PEEK and its composites have been studied. After the isothermal aging process, there is a remarkable decrease in degree of crystallinity but more organized crystallize structure achieved. As a result of transcrystalline layer formation, there was a considerable increase in the flexural modulus of materials. Thermal aging affects the impact properties of filled and unfilled PEEK dramatically. F_max, E_max and E · F_max results of both filled and unfilled aged PEEK and its composites are dramatically decreased. Thermal aging makes materials more brittle and there was a significant decrease in toughness. % Crystallinity is not the unique parameters to determine polymer’s performance. The orientation of crystals is another important parameter in microstructure and plays important role in mechanical and tribological properties of PEEK and its composites. There is a close relationship between thermal aging and microstructure. But there is not a linear relationship between microstructure and tribological properties. Microstructural changes after thermal aging serves developed mechanical properties. Increased mechanical properties results in improved tribological properties.     

Surface oxidation of carbon fibre on tribological properties of PEEK composites

Abstract

In this work, ozone modification method and air oxidation were used for the surface treatment of polyacrylonitrile (PAN) based carbon fibre. The surface characteristics of carbon fibres were characterised by X-ray photoelectron spectroscopy. The interfacial properties of carbon fibre reinforced PEEK (CF/PEEK) composites were investigated by means of the single fibre pull-out tests. As a result, it was found that IFSS values of the composites with ozone treated carbon fibre are increased by 60% compared with that without treatment. X-ray photoelectron spectroscopy results show that ozone treatment increases the amount of carboxyl groups on carbon fibre surface, thus the interfacial adhesion between carbon fibre and PEEK matrix is effectively promoted. The effect of surface treatment of carbon fibres on the tribological properties of CF/PEEK composites was comparatively investigated. Experimental results revealed that surface treatment can effectively improve the interfacial adhesion between carbon fibre and PEEK matrix. Thus the wear resistance was significantly improved.     

碳纤维增强聚醚醚酮复合材料的形状记忆效应

为推动形状记忆聚合物在空间等极端恶劣环境中的应用,以超薄碳纤维增强聚醚醚酮(Carbon fibers reinforced polyether-ether-ketone,CF/PEEK)预浸料为实验对象,采用薄膜叠层与热压成型工艺制备厚度为0.036 mm超薄预浸料的层合片材,研究了其在热应力驱动下的形状记忆行为。结果表明,在320℃加热-冷却热循环温度场的作用下,CF/PEEK复合材料超薄层合板的初始变形的形状回复率近似可达100%,当变形循环达到100次时,其形状回复率仍然可以保持在90%以上。此外,根据层合板变形的温度与应力-应变关系,解释了CF/PEEK复合材料的热应力驱动变形机制。在此基础上,改变CF/PEEK层合板厚度进行仿真设计,实现了初始状态与深海珊瑚形状、立方体、灯笼草形状之间的变形与回复。利用记忆变形产生的机械夹紧力,完成了硬币抓取实验,验证了CF/PEEK复合材料在主动变形结构应用的可行性。      

Improved mechanical and tribological properties of A356 reinforced by MWCNTs

The objective of this paper is to investigate the effect of Multi-Walled Carbon Nanotubes (MWCNTs) content on microstructure and dry sliding wear behavior of hypo-eutectic A356Al–Si alloy Metal Matrix Nano-Composites (MMNCs). Composites containing 0.5, 1.5, and 2.5 wt.% MWCNTs were prepared by rheocasting technique followed by squeeze casting. Characterization of nanocomposites was done by scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX), dry sliding wear tests were performed in a pin-on-disk wear tester against a steel disk at various speeds and normal loads. Results revealed that a decrease in both wear rate and friction coefficient of the nanocomposites considerably with the increase of MWCNT's content. The formation of the hard compact transfer layer on the pin surface nanocomposites assisted in increasing the wear resistance of these materials. It is that the transfer layer which was formed under an applied load of 20 N can act as a protective layer and help in reducing the wear rate. The results indicate the nano composites could be used in light-weight applications where moderate strength and wear properties are needed.     

碳纤维增强树脂基复合材料的应用研究进展

简述了碳纤维增强树脂基复合材料的性能特点及各种成型工艺,结合该复合材料的优异性能,介绍其在航空航天、交通运输、风电、医疗等领域的应用进展.最后对碳纤维增强树脂基复合材料的发展前景及可回收利用前景进行了展望.     

The roles of nano-SiO2 particles on the tribological behavior of short carbon fiber reinforced PEEK

In the present work, the roles of low-loading (1 vol.%) nano-SiO₂ particles (13 nm) on the tribological behavior of short carbon fiber (SCF)/PTFE/graphite (micro-sized) filled PEEK were investigated. Tribological tests were carried out at room temperature in extremely wide pressure and sliding velocity ranges, i.e. from 1 MPa to 7 MPa and from 1 m/s to 2 m/s, respectively. Under all conditions studied, the nanopartilces remarkably reduce the friction coefficients. With respect to the wear rates, however, the roles of the nanoparticles show a strong dependence on the sliding conditions. Under 1 MPa, the abrasiveness exerted by possible nano-SiO₂ agglomerates seems to accelerate SCF destructions. Under pressures higher than 2 MPa, however, the nanoparticles remarkably reduce the wear rate. This effect is more pronounced under high pressures and especially at high sliding velocities. The protection of SCF/matrix interface by the nanoparticles is supposed to be the main reason for the enhancement of the wear resistance.     

碳纤维织物/PEEK热塑性树脂基复合材料光学反射镜研究

研究了碳织物增强热塑性PEEK树脂基复合材料的力学性能、部分空间性能及光学反射性能.研究结果表明,碳织物/PEEK复合材料具有优异的力学性能、空间性能、耐辐照性能和光学反射性能;在1×10-3Pa真空中可凝挥发物(CVCM)为0、水气回收量(WVR)为0.08%,并制成φ128mm反射镜,测试了反射镜的反射率为96.89%.碳织物增强热塑性PEEK树脂基复合材料是一种适合空间环境的高性能复合材料,可以用于制作光学反射镜.     

基于导热板的碳纤维增强聚醚醚酮复合材料感应焊接温度调控

研究了碳纤维增强聚醚醚酮(CF/PEEK)复合材料感应焊接中厚度方向及焊接面内的温度分布及调控.基于对温度分布结果的分析,使用导热板结合真空袋压的方式对CF/PEEK进行感应焊接,结合使用合适的功率及加热时间,测试了焊接件的单搭接强度,观测分析了焊接件的断裂形貌.结果 表明,导热板对层合板表层和边缘均有良好的散热效果;...