三元乙丙橡胶的型别与用量对聚丙烯结晶行为的影响

采用宽角 X射线衍射法 (WAXD)和示差扫描量热法 (DSC)研究了三元乙丙橡胶的型别与用量对聚丙烯结晶行为的影响。研究表明 ,EPDM对 PP的熔点、结晶温度无明显影响 ,PP/EPDM共混物的结晶度随 EPDM组分含量的增加而降低 ,PP中除含有 α-单斜晶型外 ,还存在 β-立方晶型 ,适量的 EPDM可使 PP的晶体尺寸减少 ,晶胞参数与组分比无关     

过氧化二异丙苯和酚醛树脂对HDPE/GTR共混物的原位反应性增容

采用过氧化二异丙苯(DCP)和热塑性酚醛树脂(HY-2045)在未添加催化剂时实现了对高密度聚乙烯(HDPE)/废旧轮胎胶粉(GTR)共混物的原位反应性增容, 并研究了其对共混物的微观形貌、 应力-应变曲线、 动态力学性能和结晶性能的影响. 扫描电镜结果显示, 共混物橡塑界面处有大量的纤维状物质同时嵌入到基体相和分散相中, 使得共混物的界面强度得到显著增加, 从而获得较好的综合力学性能. 差式扫描热量(DSC)和X射线衍射(XRD)测试结果表明, 原位增容后的共混物的结晶度显著降低, 致使其明显的拉伸屈服现象消失. 由于反应型增容剂DCP和HY-2045使得共混物在界面处形成化学交联, 尽管其结晶度有所降低, 但是其拉伸强度和断裂伸长率还是得到了显著的增加. 另外, 动态力学性能测试表明, 增容后的HDPE/GTR共混物中GTR相的玻璃化转变峰变宽, 玻璃化转变温度升高.     

技术文摘专栏

TPI用量对TPI／NR并用胶微观结构的影响 【摘要】：研究反式1，4-聚异戊二烯（TPI）用量对TPI／NR并用胶微观结构的影响。试验结果表明，随着TPI用量的增大，TPI／NR并用胶中TPI球晶区域增大，当TPI用量为20份时结晶区由分散变为连续；TP}用量对TPI／NR混炼胶中TPI结晶度影响不大，TPI结晶破坏的主要因素是硫化；随着TPI用量增大，TPI／NR硫化胶中TPI微晶增多。     

过氧化二异丙苯和酚醛树脂对HDPE/GTR共混物的原位反应性增容（英文）

采用过氧化二异丙苯(DCP)和热塑性酚醛树脂(HY-2045)在未添加催化剂时实现了对高密度聚乙烯(HDPE)/废旧轮胎胶粉(GTR)共混物的原位反应性增容,并研究了其对共混物的微观形貌、应力-应变曲线、动态力学性能和结晶性能的影响。扫描电镜结果显示,共混物橡塑界面处有大量的纤维状物质同时嵌入到基体相和分散相中,使得共混物的界面强度得到显著增加,从而获得较好的综合力学性能。差式扫描热量(DSC)和X射线衍射(XRD)测试结果表明,原位增容后的共混物的结晶度显著降低,致使其明显的拉伸屈服现象消失。由于反应型增容剂DCP和HY-2045使得共混物在界面处形成化学交联,尽管其结晶度有所降低,但是其拉伸强度和断裂伸长率还是得到了显著的增加。另外,动态力学性能测试表明,增容后的HDPE/GTR共混物中GTR相的玻璃化转变峰变宽,玻璃化转变温度升高。     

Ekonol/PEEK复合材料的制备和摩擦学性能

用机械共混-模压法制备了Ekonol／PEEK复合材料，通过摩擦磨损实验方法对材料的摩擦学性能进行了研究，并用SEM对磨损表面进行了观察和分析，在此基础上探讨了复合材料的磨损机理。结果表明：用机械共混-模压法能制得摩擦学性能优良的Ekonol／PEEK复合材料，随着Ekonol含量的增加，复合材料的磨损机理发生了由微切削，剥层，粘着磨损向疲劳磨损的转变。     

聚合物填充聚四氟乙烯复合材料的摩擦磨损性能

采用机械共混-冷压成型-烧结的工艺制备了PEEK、PPS填充PTFE基粘弹．摩擦型阻尼材料，用环-块式磨损试验机研究了在干摩擦条件下的摩擦磨损性能；用扫描电子显微镜观察磨损表面形貌和内部组织结构。结果表明：混合填充PEEK和PPS时，2种填充物的比例对材料的摩擦因数影响不大，当二者含量相近时，摩擦因数最大；填充物对磨损性能的影响与对摩擦因数的相同；随着PEEK含量的增加和PPS含量的减少，材料的磨损方式由疲劳剥落磨损为主转变为犁削、粘着磨损；PTFE含量的增加，使得复合材料的摩擦因数减小，而磨损有所增大。综合考虑认为，PTFE与适当比例的PEEK／PPS混合填充，具有合适的摩擦因数和较好的耐磨性，能够满足特殊工况下阻尼材料的需要。     

振动力场强化热塑性弹性体性能研究

采用DSC、X射线衍射、TGA和FT-IR对稳态与动态条件下加工的TPE试样的结晶行为、热性能、相容性及其形态结构进行了测试,实验分析结果表明,振动力场的引入可以提高动态硫化EPDM/PP共混物的融熔温度和制品的耐热性能,结晶组分PP的结晶度降低。振动力场强化了EPDM与PP两相间的结合,使得大分子链段发生断裂和分解所需温度增大,提高了TPE的热稳定性能。随着振动强度的增加,最大失重速率温度升高,最大失重率减小,振动力场对EPDM与PP两相之间大分子链段的相互渗透与缠结作用增强,EPDM与PP非晶区的相容性提高,从而改善了TPE的性能。     

聚醚醚酮填充聚四氟乙烯摩擦学性能

采用共混-冷压-烧结的工艺制备聚醚醚酮（PEEK）填充聚四氟乙烯（PTFE）复合材料,考察 PEEK 含量对 PTFE /PEEK 复合材料的力学性能和摩擦学性能的影响,用扫描电子显微镜（SEM）观察其磨损表面和对偶表面形貌,并探讨磨损机制。结果表明：复合材料的拉伸强度随着 PEEK 含量的增加而降低,在一定范围内,冲击强度随着PEEK 含量的增加而增大;随着 PEEK 含量的增多,摩擦因数呈现先减小后增大的趋势,体积磨损率则逐渐减小。当PEEK 质量分数为20％时,复合材料耐磨性较纯 PTFE 提高了近700倍,其原因在于 PEEK 的加入改变了磨屑形成机制,并能形成均匀连续的转移膜,进而降低了磨损。     

溅射气压和衬底温度对Si1-xGex薄膜结构和光吸收性能的影响

采用射频磁控溅射法沉积了Si1-xGex薄膜,研究了溅射气压、衬底温度对薄膜结构、厚度、表面形貌、表面成分及光吸收性能的影响。结果表明:薄膜均为微晶结构且相组成不随溅射气压和衬底温度的改变而改变;随着溅射气压升高,薄膜结晶性能降低,升高衬底温度使其结晶性能提高;随气压或温度的升高,薄膜厚度均先增大后减小,在1.0Pa或400℃达到最大值;随温度的升高,薄膜表面团簇现象消失并变得平整致密,气压为8.0Pa时,表面有孔洞和沟道;随气压升高,薄膜中锗含量降低,光吸收强度减小,光学带隙增大;衬底温度的变化对光学带隙影响不大。     

聚醚醚酮复合材料的转移膜研究

用物理共混-模压法制备了Ekonol／PEEK和Ekonol／石墨／MoS2／PEEK复合材料，通过摩擦磨损实验方法对材料的耐磨件能进行了研究，并用SFM对对偶件表面进行了观察和分析，以探讨对偶面上转移膜的特性对复合材料耐磨性能的影响，结果表明：PEEK能在对偶面上形成不连续、厚薄不均的转移膜；Ekonol的加入能促进转移膜的形成；Ekonol和固体润滑剂能协同改善PEEK所形成转移膜的质量，从而提高PEEK的耐磨性能；复合材料在其对偶面上形成的转移膜质量的好坏对其耐磨性能产生直接影响。     

Tribological studies of poly(ether ether ketone) blends

A review of friction and wear studies of poly(ether ether ketone) (PEEK) blended with other polymers is presented. PEEK is a high performance thermoplastic now commonly employed in many engineering applications, but its tribological properties deteriorate in high temperature environments. One approach to improving the friction and wear properties of PEEK is to blend this plastic with appropriate polymers. In recent years, a number of investigations into the tribology of PEEK blended with poly(ether imide) (PEI), polytetrafluoroethylene (PTFE) and liquid crystalline polymers (LCPs) have been reported and these studies are discussed.     

Tribo-investigation on PTFE lubricated PEEK in harsh operating conditions

A series of blends with Polytetrafluroethylene (PTFE) powder and Polyetheretherketone (PEEK) was developed by varying the PTFE contents in steps of 5 wt.% from 0 to 20 wt.%. The composites were evaluated for their friction and wear properties at room temperature as well as high temperature in low amplitude oscillating wear (LAOW) mode against steel (100 Cr 6) ball against polymer plate. The same blends were also evaluated in abrasive wear mode to study the influence of harsh operating conditions on wear and friction performance. Incorporation of PTFE benefited PEEK in various ways such as it increased the tribo-utility of the latter by increasing its limiting load value, removing its stick-slip tendency, lowering coefficient of friction and specific wear rate significantly. With increase in PTFE content, benefits to the wear performance increased regularly. This was not the case for friction coefficient. Lowest μ was recorded for 15% PTFE contents. The enhancement in wear and friction performance, however, was at the cost of strength properties which decreased substantially with increase in PTFE content. At 100 °C, friction coefficient and wear rates of all blends increased marginally. In abrasive wear mode, on the other hand, PTFE filled PEEK showed poorer wear resistance than neat PEEK. This was correlated with strength properties and it was observed that these blends closely followed the predictions of Ratner–Lancaster plot. SEM was used to examine the micro-structural features of worn surfaces.     

Microstructure of PTFE-Based Polymer Blends and Their Tribological Behaviors Under Aqueous Environment

Four polytetrafluoroethylene-based polymer blends (PTFE blends) with polyimide (PI), polyether ether ketone (PEEK), poly(phenyl p-hydroxybenzoate) (PHBA), and perfluoroethylene propylene copolymer (FEP) were prepared by compression molding and follow-up sintering. Their microstructure was observed by scanning electron microscope. And the tribological behaviors of PTFE blends sliding against 316 steel under pure water and sea water lubrication were comparatively evaluated using block-on-ring tribology test rig. The worn surface of counterpart was examined by X-ray photoelectron spectroscopy. The results showed that by blending with the four polymers, PTFE exhibited the transformed microstructure and improved wear resistance. Compared with FEP, rigid polymers PI, PHBA, and PEEK can enhance the wear resistance of PTFE greatly because they can effectively improve the load-carrying capacity of PTFE matrix and can more efficiently prevent the crystalline bands of PTFE from being pulled out. However, because of the weak inhibition on the pulling out of PTFE crystalline bands, FEP cannot enhance the wear resistance of PTFE as significantly as other polymers. In addition, the friction coefficients and wear rates of PTFE and its blends were lower under the lubrication of sea water than under the lubrication of pure water, which was ascribed to more excellent lubricating effect of sea water originating from the deposition of CaCO₃ and Mg(OH)₂ onto the sliding surfaces.     

Formability analysis for enhancing forming parameters in AA8011/PP/AA1100 sandwich materials

The remarkable nonlinearity between the viscosity and temperature significantly reduces the extrusion formability of Nylon-66. The conventional extrusion methods, which obtain extrusion profiles with high precision through first extrusion and then sizing in calibrator, are unable to realize the extrusion of Nylon-66, especially for GF/Nylon-66 composite. In this paper, a one-step extrusion method, which realizes the fast sizing of extruded parts by taking advantages of the crystallization of GF/Nylon-66 melt, was proposed based on the viscosity change features and crystallization behavior of GF/Nylon-66 around its melting temperature (T _m). Thus, the sizing and cooling processes using standardized dies in conventional extrusion methods can be eliminated. In this study, the one-step extrusion process of GF/Nylon-66 was investigated from three aspects including the extrusion rheological performance, the equilibrium property of extrusion flow and crystallization sizing behavior, based on finite element simulations and experiments. The results revealed that the melt flow property can be improved by increasing temperature and shear rate. The rheological constitutive equation can precisely describe the rheological performance of materials under different temperatures and shear rates. Increasing melt temperature and screw speed will reduce the melt flow equilibrium. With the melt temperature at neck ring mold being the peak crystallizing temperature and screw speed being appropriate, an optimized dynamic balance among the melt flow property, the flow equilibrium performance and the crystallization sizing capability can be achieved. Thus, the extrusion molding of GF/Nylon-66 can be implemented via one-step extrusion. The method proposed can realize the extrusion molding of GF/Nylon-66 with improved efficiency and reduced cost.     

纳米粒子及PTFE填充PEEK复合材料摩擦特性的载荷和时间依赖性

以热压成型法制备了纳米Al2O3和纳米TiO2分别与聚四氟乙烯(PTFE)填充PEEK复合材料,利用自制销-盘摩擦磨损试验机研究了干摩擦条件下复合材料的摩擦行为。结果表明：复合材料的摩擦因数依赖于材料中纳米粒子的种类和含量,并对载荷有明显的依赖性;当纳米Al2O3的质量分数为5％～7％时,PEEK复合材料的摩擦因数和比磨损率最低;随着外加载荷的变化,摩擦因数呈现一定的变化规律。     

Fretting Wear Study of PEEK-Based Composites for Bio-implant Application

The failure caused by fretting wear is a key issue in orthopedic applications as well as other engineering applications. In this study, fretting wear tests were conducted on poly (ether ether ketone) (PEEK), glass fiber reinforced PEEK (GFRPEEK) and carbon fiber reinforced PEEK (CFRPEEK), respectively. Surface characterizations of tested specimens were performed using XRD, microhardness tester, 3D white-light interfering profilometry, SEM and optical microscopy to analyze their wear features. The obtained results showed that the fibers increased the microhardness values and reduced the friction coefficients and wear rates of PEEK-based composites. The fretting regimes of PEEK, GFRPEEK and CFRPEEK were gross slip. The fretting wear mechanisms of those PEEK composites were dominated by abrasive wear, adhesive wear and delamination. CFRPEEK has demonstrated superior fretting wear characteristics, and hence, is a potential bio-implant material for applications such as artificial joints.     

聚醚醚酮3D打印成形工艺的仿真和实验研究

为解决高性能医用聚醚醚酮（polyethoretheretherketone,PEEK）零件复杂结构难以加工的问题,采用基于熔融沉积原理的3D打印方式,辅以高温成形腔体结构,通过模拟仿真和工艺实验,开展PEEK的快速成形系统工艺研究。仿真结果表明：采用接近PEEK玻璃化温度的高温成形腔体环境,可以明显地减小PEEK试样的翘曲变形；采用较小内径的喷嘴,有利于PEEK丝材的熔化和熔融挤出稳定性。实验数据表明：喷嘴内径0.4 mm和打印层厚0.1 mm的设置条件下,PEEK试样的最高平均拉伸强度可达到74.74 MPa,接近传统注塑成形零件的拉伸性能。     

Tribological Behaviour of Polymeric Coatings: II. SCF‐Reinforced PEEK Nanocomposite Systems

This paper focuses on coatings based on poly(ether ether ketone) (PEEK) applied to metal substrates and their tribological investigation. Short carbon fibres (SCF), graphite, and 300 nm titanium dioxide (TiO₂) and zinc sulphide (ZnS) particles were used as filler materials for the PEEK. These filler materials and their combinations were found to have a significant influence on the tribological behaviour of the corresponding PEEK compounds. One of the compounds (PEEK6) was found, especially at higher temperatures and under higher normal loads, to be a good coating material showing superior tribological behaviour. For PEEK6, a specific wear rate and a coefficient of friction (COF) lower than those for the best commercially available PEEK compound (PEEK4) were measured. For specific test parameters, PEEK6 showed a COF of less than 0.1. The tribological results were also compared with those of a conventional sliding bearing material based on poly(vinylidene fluoride) (PVDF).     

水润滑下316L不锈钢与聚醚醚酮摩擦磨损性能研究

为了寻找适合于水液压泵/马达的摩擦副材料,以316 L不锈钢与纯聚醚醚酮树脂、30%玻璃纤维增强PEEK(PEEKGF30)、30%碳纤维增强PEEK(PEEKCA30),PTFE和石墨及碳纤维填充PEEK(PEEKHPV)组成的摩擦副为研究对象,利用MMW-1立式万能摩擦磨损试验机测量摩擦副在水润滑下接触表面的摩擦因数和温度以及试样的磨损量,并通过激光共聚焦显微镜对试件表面磨损形貌进行分析。结果表明:316 L-PEEKHPV摩擦副的摩擦因数、摩擦温升、磨损量均小于其余3组摩擦副,适合作为水液压泵/马达的关键摩擦副材料。316 L不锈钢与PEEKGF30配对时,摩擦机制为涂抹和擦伤,磨损较为严重;与PEEKCA30配对时,摩擦机制为擦伤;与PEEKHPV配对时摩擦机制主要为划伤,磨损较为轻微。