碱液中晶须增强PEEK复合材料的摩擦磨损性能

研究了不同含量PTW增强PEEK复合材料在碱液中的摩擦磨损性能,并与经典的CF增强PEEK复合材料对比,借助于SEM分析了磨损面和对偶面微观形貌,探讨了相关机理。结果表明,干摩擦时15%(质量)PTW增强PTFE/PEEK复合材料耐磨性是相同含量CF增强时的10.5倍。在碱液中,CF增加了PTFE/PEEK复合材料的摩擦系数、降低了其耐磨性能,而PTW可以进一步降低PTFE/PEEK复合材料的摩擦系数、明显地提高其耐磨性能。含5%PTW可提高PTFE/PEEK复合材料碱液中耐磨性2.36倍。碱液阻止了对偶面转移膜的形成,犁削和磨粒磨损是CF增强PEEK复合材料碱液中的主要磨损机制,而隧道状晶体结构和细微尺寸的纤维态形貌使得PTW在碱液中仍具有显微增强耐磨作用。     

High performance PEEK/AlN micro‐ and nanocomposites for tribological applications

The tribological properties of poly(ether–ether–ketone) (PEEK)/aluminum nitride (AlN) composites reinforced with micro‐ and nano‐AlN particles were evaluated under dry sliding conditions. The wear resistance of pure PEEK is 10‐fold higher than mild steel. It was further improved by 2‐fold at 20 wt % micro‐AlN and by more than 4‐fold at 30 wt % nano‐AlN composite compared with pure PEEK. The improvement in wear resistance was attributed to a thin and coherent transfer film. However, it was deteriorated on further increasing micro‐AlN. The coefficient of friction of the composites was increased. Scanning electron microscopy and optical microscopy of worn surfaces and transfer films have been explained in detail. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

玻璃纤维增强PEEK复合材料成型工艺研究

本文初步探索了玻璃纤维增强聚醚醚酮(PEEK)复合材料的成型工艺．通过力学性能、微观形貌分析等试验,探索了不同工艺参数对玻璃纤维增强PEEK复合材料性能的影响,进而制定了复合材料较优的成型工艺参数．其成型工艺参数包括冷却速度、成型压力、成型温度、保温时间．     

Friction welding joint analysis of dissimilar nanocomposites: PEEK/aluminum to PEEK/titanium

Welding of dissimilar materials is extremely challenging to the researchers. In present work, for the first time, poly(ether ether ketone) (PEEK) based aluminum (Al), titanium (Ti) reinforced nanocomposites with varying reinforcements of 10, 20, 30, and 40 vol% were developed using powder metallurgy technology. Additionally, for the first time, the two dissimilar nanocomposites of PEEK/Al and PEEK/Ti were successfully welded by friction welding (FW) process to produce FW PEEK/Al-PEEK/Ti nanocomposites with equal metallic reinforcements (viz., 10–40 vol% Ti or Al). The nanocomposites were characterized precisely and correlated by physical, microstructural, structural, thermal, and micromechanical tests. Crystallinity being a factor of melting temperature affects significantly the micromechanical characteristics influenced by reinforced particle-concentrations. The FW PEEK/30Al-PEEK/30Ti was found as best material since it showed highest nanohardness (0.652 GPa) and elastic modulus (15.902 GPa) in FW Joint at 40 mN compared to other FW nanocomposites. At the FW joint section, it was discovered that the reinforced particles were being transferred through an interdiffusion mechanism. Mobility of the nanoparticles was influenced by the concentration of the reinforced particles, which further modified the matrix's crystallization behavior and consequently influenced the FW nanocomposites' micromechanical properties. Therefore, the present work has suggested a feasible route for applying thermoplastic nanocomposites in the biomedical and aerospace industries.     

Influence of cenosphere on tribological properties of short carbon fiber reinforced PEEK composites

This investigation focuses on the effects of cenosphere fillers on tribological properties of carbon fiber reinforced PEEK composites. Dry sliding wear behavior of 15 wt % short carbon fiber (SCF) reinforced PEEK composites filled with 5, 10, 15, and 20 wt % cenosphere was reported in this study, pure PEEK and 15 wt % SCF reinforced PEEK composites were also prepared for comparative analysis. Friction and wear experiments were conducted on a ring-on-block apparatus under different loads (100–400 N). The experimental results showed that all the composites exhibited lower coefficient of friction and better wear resistance than the matrix resin under different load conditions. It is noted that 10 wt % of the cenosphere particles filled SCF reinforced PEEK composites show superior tribological properties when compared to the other composites in this study. The morphologies of the worn surface and the fracture surface were analyzed by scanning electron microscopy and the transfer film was observed by optical microscope to understand the dominant wear mechanisms. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47245.     

Preparations and properties of a high performance semicrystalline copolyimide and composites reinforced with glass fiber

A semicrystalline copolyimide derived from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (s‐BPDA), 1,3‐bis‐(4‐aminophenoxy)benzene (TPER), and 4,4′‐oxydianiline (4,4′‐ODA), end capped with phthalic anhydride (PA), was synthesized. Glass fiber reinforced composite was also prepared by impregnating powdery glass fiber with poly(amic acid) followed by solution imidization techniques. This copolyimide displayed a glass transition temperature of 202°C and a melting temperature of 373°C by differential scanning colorimeter (DSC). Crystallization and melting behaviors were investigated under nonisothermal and isothermal crystallization conditions. Double exothermic peaks were found by DSC when the copolyimide was cooled from the melt and multiple melting behaviors can be observed after the coployimide had been isothermally crystallized at different temperatures. Mechanical properties were investigated by dynamical mechanical analysis (DMA) and tensile experiments. The samples were cured at different temperatures and then tested at different temperatures. Results indicated that the copolyimide and the composite showed excellent mechanical properties. Additionally, this copolyimide also showed lower melt viscosity by rheological analysis. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40345.     

Preparation and performance of aluminum borate whisker–reinforced epoxy composites. I. Effect of whiskers on processing,reactivity, and mechanical properties

Aluminum borate (Al₁₈B₄O₃₃) whisker–reinforced composites based on a epoxy resin, which was made up of a trifunctional epoxy resin, TDE 85, and methyl nadic anhydride (MNA), were prepared, and the effects of the whiskers on the processing, reactivity, and typical mechanical properties of the composites were investigated. Two coupling agents, aluminate (DL411A) and borate (BE4), were used to surface treat the whiskers. Results show that the addition of the whiskers does not change the reactivity of the matrix, while increasing the viscosity of the resin, but when the whisker content is less than 5 wt %, the increased viscosity does not obviously influence the processing characteristics of the resin. Mechanical properties are greatly dependent on the chemistry and concentration of the coupling agent for treating the whiskers. A good coupling agent, which has good interaction with the whiskers and the matrix, can effectively improve the compatibility between the whiskers and the matrix, and thus result in great improvement of mechanical properties. BE4 proved to be better than DL411A for treating the whiskers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1950–1954, 2004     

Mechanical properties of graphene oxide reinforced alumina matrix composites

Graphene oxide (GO) reinforced alumina matrix composites have been fabricated by using graphene oxide synthesized by a modified Hummer's method. Samples were prepared by powder metallurgy and consolidated by Spark Plasma Sintering (SPS). The influence of GO addition on the microstructure and mechanical properties of the composites was investigated. Results show a significant increase (almost 35%) of the fracture toughness for composites containing 0.5 wt% graphene oxide compared to sintered pure alumina. In order to find reasons for this improvement Scanning/Transmission Electron Microscopy (SEM/TEM) observations were carried out. They reveal a good interface between the reinforcement and the matrix as well as such mechanisms like branching, deflection and bridging of crack propagation.     

Preparation,structures and properties of interpenetrating network structure-type Phosphate/PEEK composites with enhanced compressive strength and high temperature resistance

Phosphate/polyether ether ketone (PEEK) composites were successfully prepared by molding method and thermal treating at the temperature of 360 °C. The structures and compositions of phosphate/PEEK composites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and scanning electron microscopy. The mechanical properties thermal resistance and dielectric properties were strictly evaluated by the mechanical testing, thermogravimetric analysis and dielectric constant analysis. As the results, the interpenetrating network structure (IPNS) of Al₂O₃-phosphates was completely formed in PEEK matrix. And the phosphate/PEEK composite with 40% Al₂O₃-phosphate showed a 15.9% increasing for tensile strength and 74.5% increasing for compressive strength at room temperature. Besides, the phosphate/PEEK composite with 80 wt% Al₂O₃-phosphate dispalyed a dielectric constant of 4.0, a dielectric loss of 0.0601 and a Shore hardness of 91 HD. As the structural materials, these composites would exhibited the potential applications in aviation, aerospace and other fields.     

PEEK/diatomite composites by in situ polymerization: Synthesis,characterization and fundamental properties

In this study, poly (ether ether ketone)/diatomite composites (PEEK/diatomite composites) were prepared by in situ polymerization. In contrast to the direct melt-compounding method, particles are produced with up to 25 wt % higher filler content by the in situ polymerization method. We found that filling with diatomite improved the mechanical properties of PEEK by about 15%. Scanning electron microscopy revealed that the diatomite particles are uniformly dispersed in the PEEK matrix. Furthermore, the PEEK resin penetrates into the diatomite channels to form interpenetrating organic–inorganic network structures. The thermal stabilities of the composites were studied by thermogravimetric analysis, which revealed that they possess excellent thermal stabilities; these PEEK/diatomite composites exhibit higher decomposition-onset temperatures than virgin PEEK and lower rates of decomposition. This is attributable to interactions between the diatomite and the matrix, with the diatomite acting as a physical barrier between the polymer and the superficial zone where polymer combustion takes place. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46983.     

短碳纤维增强铝基复合材料

通过化学镀再电镀的方法,在碳纤维表面镀上Cu镀层,制备C/Cu复合丝,并在硼酸的保护下,利用非真空条件下的液态机械搅拌法制备短碳纤维增强铝基复合材料,研究了碳纤维在复合材料中的分散程度,铜镀层存在状态及C/Al复合材料的拉伸性能.实验结果表明：在硼酸存在下,大大降低了铜的氧化程度,碳纤维分散均匀且没有损伤,少量硼酸的加入,对复合材料的力学性能没有影响,该复合材料的抗拉强度随碳纤维含量的增加而增加,其抗拉强度较基体材料提高50%以上,但塑性指标却明显下降.     

Study on microhardness,dynamic mechanical,and tribological properties of PEEK/Al2O3 composites

The wear and friction properties of poly (ether‐ether‐ketone) (PEEK) reinforced with 0–33 vol % (60 wt %) micron size Al₂O₃ composites were evaluated at a sliding speed of 1.0 m/s and nominal pressure from 0.5 to 1.25 MPa under dry sliding conditions using a pin‐on‐disk wear tester. The wear resistance of the pure PEEK is 10‐fold higher than that of mild steel under the similar test condition. It is improved to 18‐fold as compared with mild steel at 3.5 vol % Al₂O₃ content. The improvement in wear properties may be attributed to the thin, tenacious, and coherent transfer film formed between the steel countersurface and composite pin. However, the wear resistance of PEEK containing above 3.5 vol % Al₂O₃ was deteriorated, despite their higher hardness and stiffness as compared with that of composites containing lower Al₂O₃ content. This is attributed to the formation of thick and noncoherent transfer film, which does not prevent the wear of the composites from hard asperities of countersurface. Moreover, hard Al₂O₃ particles present in transfer film act as third body wear mechanism. The coefficient of friction of the composites is higher than that of pure PEEK. SEM and optical microscopy have shown that wear of pure PEEK occurs by the mechanism of adhesion mainly whereas of PEEK composites by microploughing and abrasion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

PPS/recycled PEEK/ carbon nanotube composites: Structure,properties and compatibility

Blends of poly(phenylene sulfide) (PPS) and recycled poly(ether ether ketone) (r‐PEEK) were prepared using a twin‐screw extruder. The carbon nanotube (CNT) added to the blends not only improved the compatibility of the two polymers, but also affected the morphology of the immiscible PPS/r‐PEEK blends. R‐PEEK always forms the dispersed phase and PPS the continuous phase in such blends. In the composite, CNT particles were observed in the PPS phase, mostly distributes in the interface between PPS and PEEK. The results show that r‐PEEK improves the impact and tensile strength of PPS, but does not provide nucleation effect on PPS. However, CNT improved the flexural modulus of PPS/r‐PEEK blends and promoted the crystallization of r‐PEEK rather than that of PPS. The prepared PPS/r‐PEEK blends provided larger electrical conductivity than neat polymers. Adding 20 wt % CNT to blend resulted in composite with the minimum volume resistivity, a reduction of four orders of magnitude, compared with that of the neat blend. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42497.     

Preparation and characterization of aluminum oxide–poly(ethylene-co-butyl acrylate) nanocomposites

This article describes the preparation and characterization of composites containing poly(ethylene-co-butyl acrylate) (EBA–13 and EBA–28 with 13 and 28 wt % butyl acrylate, respectively) and 2–12 wt % (0.5–3 vol %) of aluminum oxide nanoparticles (two types differing in specific surface area and hydroxyl-group concentration; uncoated and coated with, respectively, octyltriethoxysilane and aminopropyltriethoxysilane). A greater surface coverage was obtained with aminopropyltriethoxysilane than with octyltriethoxysilane. An overall good dispersion was obtained in the EBA-13 composites prepared by extrusion compounding. Composites with octyltriethoxysilane-coated nanoparticles showed the best dispersion. The addition of the nanoparticles to EBA–28 resulted in poor dispersion, probably due to insufficiently high shear forces acting during extrusion mixing which were unable to break down nanoparticle agglomerates. The nanoparticles had no effect on the crystallization kinetics in the EBA–13 composites, but in the EBA–28 composites the presence of the nanoparticles led to an increase in the crystallization peak temperature, suggesting that the nanoparticles had a nucleating effect in this particular polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Investigation of covalently grafted polyacrylate chains onto graphene oxide for epoxy composites with reinforced mechanical performance

To enhance the dispersion and interfacial interaction of graphene–epoxy matrix, polyacrylate chains grafted graphene oxide (PA-GO) was manufactured with A-174 functionalized GO (A-GO), methyl acrylate, and glycidyl methacrylate via free-radical random copolymerization technique. Fourier transform infrared, thermogravimetric analysis, X-ray photoelectron spectrum, Raman spectroscopy, X-ray diffraction, transmission electron microscopy, and nuclear magnetic resonance were performed to investigate the structure of A-GO and PA-GO. Then, the PA-GO was incorporated into epoxy resin via in situ solution intercalation dispersion method in order to form an interpenetrating network structure with epoxy resin. Field emission scanning electron microscope results indicate that the PA-GO exhibits excellent dispersion and interfacial compatibility in the epoxy matrix. In compared with pure epoxy, the tensile strength and impact strength of the epoxy composite with 1 wt % PA-GO were shifted from 62.78 ± 2.54 to 70.68 ± 2.02 MPa (about 12.6%) and 3.55 ± 0.41 to 4.98 ± 0.33 kJ m⁻² (about 40.3%), respectively. Moreover, increased storage modulus is also observed in the dynamic mechanical analysis measurements compared with that of neat epoxy resin. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47842.     

Cone calorimeter testing of S2 glass reinforced polymer composites

With the ever increasing demand for fuel savings on vehicles, there is a strong push to replace metal with polymeric + fiber (carbon/glass) composites. However, the replacement of metal with polymeric composites can lead to additional fire risk. Our study focused on glass fiber reinforced polymer composites meant for vehicular structural applications, and flammability performance of these composites was studied by cone calorimetery. The effects of fiberglass loading, nanocomposite use (clay, carbon nanofiber) and polymer type (epoxy, phenolic) were studied under a heat flux of 50kW/m² to better understand the potential effects that these variables would have on material flammability. It was found that as fiberglass loading increased, flammability decreased, but at a cost to structural integrity of the residual polymer + fiber char. The use of nanocomposites has little effect on reducing flammability in this set of samples, but the use of phenolic resins in comparison with epoxy resins was found to yield the greatest improvements in flammability performance. Further, the phenolic system yielded a higher level of structural integrity to the final polymer + fiberglass char when compared with the other polymer systems of low heat release. Copyright © 2009 John Wiley & Sons, Ltd.     

Application of raman microscopy to the analysis of high modulus polymer fibres and composites

Raman microscopy has been used to study the deformation of carbon fibres and an experimental grade carbon-fibre/PEEK composite prepreg. It has been found that the peak position of the Raman-active bands in the fibres are sensitive to the level of applied strain. Examination of the peak positions from the carbon fibres near the surface of the prepreg shows that the fibres are subjected to a residual compressive strain. The application of a tensile stress to the composite causes the fibre strain to become tensile although significant scatter is found in the measurements. The scatter is thought to be due to variations in the local carbon-fibre strain at the 1 μm level. It is demonstrated that residual compressive strain is expected from differential shrinkage between the fibres and matrix on cooling the composite from the processing temperature to room temperature.     

Mechanical properties of natural carbon black reinforced polymer composites

This article describes the development of new carbon black material from agricultural waste (wood apple shells) by using pyrolysis method at various carbonization temperatures (400, 600, and 800°C) and used as reinforcement in polymer composites. The wood apple shell carbon black (WAS‐CB) particulates are characterized by proximate analysis, energy dispersive spectroscopy (EDS), and scanning electron microscope (SEM). Results showed that due to increases in carbonization temperature the percentage of carbon improved in the carbon black particles. Furthermore, various tests were performed to determine the effect of new carbon black material on the mechanical properties of composite at different filler loading. The results indicated that mechanical properties like tensile strength, tensile modulus, flexural strength, and flexural modulus are improved as the increase in the carbonization temperature and filler loading. The filler‐matrix bonding was analyzed by SEM. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41211.     

改性氮化铝/环氧树脂复合材料的制备研究

采用共混-浇注成型法制备氮化铝/环氧树脂AlN/E-51复合材料。借助静止沉淀法、接触角、傅立叶红外光谱FT-IR和热失重TGA等进行分析表征。探讨了AlN用量和表面改性对复合材料力学性能的影响。结果表明,KH-560以化学键结合在AlN表面。复合材料的弯曲和冲击强度均随AlN用量的增加而提高,当AlN用量为10%时,复合材料的力学性能最佳。()()()