聚醚醚酮与不同硬质涂层配副的摩擦学行为对比

目的 对比聚醚醚酮(PEEK)与不锈钢、CrN涂层、Cr/GLC多层涂层3种配副的大气环境摩擦学行为。方法 采用多靶磁控溅射镀膜技术在17–4PH不锈钢基底表面制备CrN涂层和Cr/GLC多层涂层。采用摩擦磨损试验机和三维轮廓仪对配副摩擦因数和磨损率进行测试,采用扫描电镜、拉曼光谱仪和显微红外光谱仪等方法,表征不同配副摩擦前后的表面物理化学状态,剖析涂层与PEEK配副的磨损机理。结果 CrN涂层和Cr/GLC多层涂层均显著提高了不锈钢基底的摩擦性能,相较于PEEK与17-4PH不锈钢配副,CrN涂层和Cr/GLC多层涂层的摩擦因数都显著降低。此外,涂层的磨损率分别降低了93.1%、97.4%;对应PEEK配副的磨损体积也分别降低了35.1%和65.8%。在3种配副条件下,PEEK摩擦后均发生了芳香环的开放、取代、交联,以及不同程度的结晶度损失,结晶度的顺序为未磨PEEK>PEEK–Cr/GLC>PEEK–CrN> PEEK–17-4。结论 CrN涂层的硬度、粗糙度较高,且缺少润滑,黏着磨损更显著,PEEK材料发生了大量转移,转移材料在减轻PEEK磨损的同时也阻止了结晶度的降低。PEEK与Cr/GLC多层涂层配副表现出最佳的耐磨损性能,主要归因于摩擦时PEEK结晶度的维持及GLC中富石墨相赋予涂层的低剪切润滑作用。     

Dynamical Integration of Antimicrobial,Anti-Inflammatory,and Pro-Osteogenic Activities on Polyetheretherketone via a Porous N-Halamine Polymeric Coating

Polyetheretherketone (PEEK) has been widely used as orthopedic implants, but the poor antimicrobial and osseointegration properties hinder its advanced clinical applications. Most of the modification strategies are difficult to temporally fulfill initial broad-spectrum antimicrobial and later pro-osteogenic requirements for a long-term success of implantation. N-halamine is a kind of biofriendly antimicrobial agent, and its functional N─Cl groups could be converted into N─H groups, potentially resulting in new bioactivities. Therefore, it is supposed that N-halamine might provide a feasible design for the dynamical integration of antimicrobial and pro-osteogenic abilities. Herein, a new class of surface-porous PEEK implant with an N-halamine polymeric coating (sp-PEEK-NCl) is constructed by successive pore-making, polymer grafting, and chlorination. The as-prepared sp-PEEK-NCl exhibits broad-spectrum antibacterial, antifungal, anti-inflammatory, and pro-osteogenic effects. More importantly, with the consumption of oxidative chlorine, the N─Cl groups in sp-PEEK-NCl are transformed into N─H groups with enhanced pro-osteogenic ability, endowing sp-PEEK-NCl with dynamically compatible bioactivities for osseointegration in different periods after implantation. Rat implant-associated osteomyelitis model confirms that sp-PEEK-NCl obviously reduces infectious bone destruction and promotes osseointegration in vivo. This work may provide a promising strategy for intelligent integration of bioactivities and valuable insight into the design of orthopedic implants in bone tissue engineering.     

Fundamentals, processes and applications of high-permittivity polymer-matrix composites

There is an increasing need for high-permittivity (high-k) materials due to rapid development of electrical/electronic industry. It is well-known that single composition materials cannot meet the high-k need. The combination of dissimilar materials is expected to be an effective way to fabricate composites with high-k, especial for high-k polymer-matrix composites (PMC). This review paper focuses on the important role and challenges of high-k PMC in new technologies. The use of different materials in the PMC creates interfaces which have a crucial effect on final dielectric properties. Therefore it is necessary to understand dielectric properties and processing need before the high-k PMC can be made and applied commercially. Theoretical models for increasing dielectric permittivity are summarized and are used to explain the behavior of dielectric properties. The effects of fillers, fabrication processes and the nature of the interfaces between fillers and polymers are discussed. Potential applications of high-k PMC are also discussed.     

碳酸钙晶须增强聚醚醚酮自润滑复合材料的动态力学行为

利用热压成型法制备碳酸钙(CaCO3)晶须和聚四氟乙烯(PTFE)填充的聚醚醚酮(PEEK)基自润滑复合材料.用动态热机械分析仪测试了复合材料的动态力学性能.得到了储能模量、耗能模量及损耗因子随温度变化(25～300℃)的曲线,并和纯PEEK进行比较,分析填充组分对PEEK动态力学性能的影响.结果表明:CaCO_3/PEEK复合材料在玻璃化转变温度(Tg)以下的储能模量比纯PEEK大幅度提高,且随着晶须含量增加而增加;在Tg温度以上,CaCO_3/PEEK复合材料储能模量相对纯PEEK仍保持较高的水平,显著提高了复合材料的高温刚性和热变形温度.加入PTFE使CaCO_3/PEEK复合材料在Tg温度以下的储能模量有所降低,但在Tg温度以上没有衰退.CaCO_3晶须和PTFE的协同作用有助于提高PEEK自润滑复合材料的摩擦学性能.     

聚醚醚酮在复合材料电连接器上的应用

叙述了复合材料电连接器的发展现状,包括聚醚醚酮材料在复合材料电连接器上应用的优势;同时,介绍了聚醚醚酮材料的注射成型工艺和模具结构设计要点,着重阐述了聚醚醚酮材料的表面处理技术和镀层质量检验,指出了该材料注射成型和表面处理的关键点,表明了聚醚醚酮在军用复合材料电连接器上的适用性和重要性。     

Transient finite element analysis of ultrasonic welding of PEEK

Finite element method was adopted to investigate the temperature profile during ultrasonic welding of PEEK （polyetheretherketone ）. The comparison of temperature fields was made among the triangular, semicircular and rectangular energy directors. The results show that the highest temperature appears on the sample surfaces in the welding interface. For triangular and semicircular energy directors, the gradient of their temperature fields become larger with welding amplitude increasing, and the temperature decreases along the normal line of surface. The melting point can be rapidly reached before large scale plastic deformation occurs as welding amplitude exceeds 25 μm for triangular energy and 35 μm for semicircular energy director. But for the rectangular energy director, its temperature field is dispersed even under 35μm welding amplitude.     

阀片材料为聚醚醚酮的压缩机气阀设计与应用

介绍了聚醚醚酮（PEEK）的性能,分析了阀片材料为PEEK的气阀相对于阀片材料为金属气阀的优缺点,列举了PEEK在活塞压缩机气阀中的工程应用案例。理论分析与工程应用结果表明,PEEK是一种制造活塞压缩机气阀阀片较为理想的材料,值得大力推广应用。     

Comparative Study on Tribological Behaviors of Polyetheretherketone Composite Reinforced with Carbon Fiber and Polytetrafluoroethylene Under Water-Lubricated and Dry-Sliding Against Stainless Steel

The tribological behaviors of the composites of polyetheretherketone (PEEK) reinforced by carbon fiber and polytetrafluoroethylene (PTFE) under distilled-water-lubricated- and dry-sliding against stainless steel were investigated. It was found that the PEEK composite had much better wear-resistance under water-lubricated sliding against stainless steel than under dry-sliding. The transfer film had smaller effect on the tribological behavior of PEEK composite under water-lubricated condition than under dry-sliding, because under water-lubricated condition the cooling and boundary lubricating effects of the water medium dominated the tribological behavior. Moreover, the considerably hindered transfer of the PEEK composite under water lubrication might also account for the decreased wear rate under water lubrication. The PEEK composite was characterized by mild scuffing and fiber protruding under water lubrication, while the plastic deformation and adhesion was significantly abated than under dry-sliding.     

PEEK polymer flammability and the inadequacy of the UL‐94 classification

Fire safety is dependent on reliable information on material properties, particularly relating to burning behaviour. The Underwriters Laboratory UL‐94 test is a widely used simple Bunsen burner test for vertically upward flame spread. Aryl polyetheretherketones (PEEK) are polymers of exceptional thermal stability, typically decomposing at around 600°C and forming 50% carbonaceous char residue. Tests on seven PEEK polymers, and two related materials, in independent laboratories have revealed large inconsistencies in both the final broad classification and the scatter within each set of test results. In many cases, this variance is so large that if samples from the same batch of many of the materials were repeatedly submitted to test laboratories, this would ultimately result in one set remaining below the maximum burn time criteria, and so meeting the least flammable V‐0 rating. Initial data are presented indicating that a larger ignition source actually results in shorter burning times and more consistent burning behaviour. The reported behaviour of PEEK indicates that the inconsistencies reported here are not a function of inconsistencies in the material itself but rather a consequence of the low applied heat flux of the test method being very close to the critical heat flux for ignition of the PEEK polymer, which is rather high. With higher applied heat fluxes, this generates sufficient heat for a protective char to form, creating an effective barrier to further flame spread. Copyright © 2011 John Wiley & Sons, Ltd.     

多孔PEEK自润滑材料的制备与摩擦磨损性能

采用模压-滤取和高温真空熔渍工艺制备了多孔聚醚醚酮(PEEK)发汗式自润滑材料,并分别考察了成型压力、造孔剂含量和润滑油脂种类对PEEK多孔自润滑材料的摩擦磨损性能的影响。结果表明,压力为100MPa,NaCl的质量分数为30%,采用通用锂基脂时,所得多孔PEEK自润滑材料的磨损率最低,200N下磨损率为2.73×10-16m3/(N.m),与纯PEEK干摩擦相比耐磨性提高了1245倍,其耐磨性较经典的炭纤维增强PEEK复合材料还提高了32倍。研究表明,多孔结构能够储存润滑油,在摩擦过程中能通过发汗作用在对偶面上形成稳定连续的油膜而起到良好的润滑作用,从而大幅降低复合材料的摩擦系数和磨损率。