The mechanical properties of insert-molded poly (ether imide) (PEI)/C fiber poly (ether ether ketone)(PEEK) composites

The mechanical properties of insert-molded poly(ether imide) (PEI)/carbon fiber poly(etheretherketone) (CF PEEK) have been examined. Bimaterial composite specimens were constructed by injecting CF PEEK into a mold containing one-half of a PEI tensile specimen. These PEI/CF PEEK composites retained much of their strength and dimensional integrity at temperatures as high as 200°C. Variations in test speed had little affect on breaking strains or stiffness. For two grades of PEI examined, properties were independent of the molecular weight of the PEI. Ultimate properties and fracture surfaces suggested good adhesion between the PEI and CF PEEK, possibly aided by miscibility between the two materials. The PEI/CF PEEK bimaterial composites behaved similarly to PC/CF PEEK specimens, but exhibited higher breaking stresses and moduli, both at room and elevated temperatures.     

Preparation and thermal properties of soluble poly(phthalazinone ether sulfone ketone) composites reinforced with multi-walled carbon nanotube buckypaper

A nanocomposite with soluble high-performance poly(phthalazinone ether sulfone ketone) (PPESK) as matrix and multi-walled carbon nanotube buckypaper (MWCNT-BP) as reinforcement was fabricated by hot-press processing. The morphologies, dynamic and static mechanical behavior, thermal stability of the MWCNT-BP/PPESK composites were studied using scanning electron microscope (SEM), dynamic mechanical analyzer (DMA) and thermogravimetric analyzer (TGA). SEM microphotographs revealed a high impregnation degree of the MWCNT-BP/PPESK composites. Dynamic and static mechanical analysis revealed that the nanocomposites possessed high storage modulus, and good retention rate of mechanical strength even at 250 °C, which is mainly attributed to satisfied impregnation and strong interactions between MWCNT-BP and PPESK. Thermogravimetric analysis exhibited that the nanocomposites had excellent thermal stability. These investigations confirm that MWCNT-BP can be effectively used to manufacture high-loading CNT/PPESK composites with improved properties.     

Effect of carbon nanotubes on the mechanical properties and crystallization behavior of poly(ether ether ketone)

Pristine carbon nanotubes (CNTs) and noncovalently functionalized carbon nanotubes (f-CNTs) were used to prepare poly(ether ether ketone) (PEEK) composites (CNTs/PEEK and f-CNTs/PEEK) via melt blending. Noncovalently functionalized multiwalled nanotubes were synthesized using hydrogen-bonding interactions between sulfonic groups of sulfonated poly(ether ether ketone) (SPEEK) and carboxylic groups of nanotubes treated by acid (CNTs–COOH). The effects of these two kinds of nanotubes on the mechanical properties and crystallization behavior of PEEK were investigated. CNTs improved mechanical properties and promoted the crystallization rate of PEEK as a result of heterogeneous nucleation. Better enhancement of mechanical properties appeared in the f-CNTs/PEEK composites, which is ascribed to the good interaction between f-CNTs and PEEK. However, the strong interaction of f-CNTs and PEEK chains decreased the crystallization rate of PEEK for high content of f-CNTs.     

Influence of processing conditions on bending property of continuous carbon fiber reinforced PEEK composites

The purpose of this study is to achieve an optimum fabrication condition for the continuous carbon fiber reinforced PEEK matrix composites based on a micro-braiding fabrication method. The composite plates were fabricated at three processing temperatures (380, 410 and 440 °C) and three holding times (20, 40 and 60 min), respectively, with a total number of nine different fabrication conditions, and their bending properties were investigated in terms of thermal and fracture characterizations. As a result, the bending performance of the fabricated composites was significantly affected at the 440 °C temperature. Although no significant change in the bending performance was seen at the 380 and 410 °C with all the holding times, the thermal and fracture characterizations implied a degradation of the PEEK matrix property during the fabrication process. In order to avoid the matrix degradation and the decrease of mechanical properties, a lower fabrication temperature with a shorter holding time should be recommended for the carbon/PEEK composites fabricated by the micro-braiding method.     

聚醚醚酮改性研究进展

聚醚醚酮(PEEK)作为一种新型高性能热塑性工程塑料,在许多工程领域有着广泛的应用.采用不同手段增强PEEK,改善其加工性能和力学性能、热性能、摩擦学性能,有利于降低材料成本和进一步拓展应用范围.本文从纤维增强PEEK、颗粒填充PEEK、PEEK表面改性、与聚合物共混等方面综述了PEEK改性研究的进展情况.     

多壁碳纳米管/杂萘联苯聚醚砜酮复合材料的制备及性能

采用溶液共混及原位复合法制备多壁碳纳米管/杂萘联苯聚醚砜酮复合材料.通过扫描电镜观察材料的形貌,并对材料性能进行研究.对比两种方法,结果表明通过原位复合法制备,碳管在基体中有较好的分散和界面结合,其力学性能和导电性优于溶液共混法制备的复合材料.当碳管含量为3%(质量分数)时,原位复合材料的拉伸模量和强度分别为2.4GPa和107.6MPa,其体积电阻率达到1.0×106 Ω·cm,5%热失重温度提高了20℃.     

Preparation and characterization of poly(ether ether ketone)/poly(ether imide) [PEEK/PEI] blends for fused filament fabrication

Journal of Materials Science - The present study focuses on the preparation and characterization of a poly(ether ether ketone)/poly(ether imide) [PEEK/PEI] blend for application in additive...     

Transfer film growth of continuous carbon fiber reinforced thermoplastic poly(ether ether ketone) facilitated by surface texture during dry sliding

Journal of Materials Science - To show the effect of surface texture on transfer film growth of continuous carbon fiber-reinforced thermoplastic poly(ether ether ketone) (CCF-PEEK), tribological...     

Design and preparation of graphene/poly(ether ether ketone) composites with excellent electrical conductivity

Graphene/poly(ether ether ketone) (m-TRG/PEEK) composites with excellent electrical conductivity were fabricated by hot pressing technique with thermally reduced graphene nanosheets (m-TRG) which were modified by poly(ether sulfone). Moreover, the conductive, thermal, and mechanical properties of PEEK/m-TRG composites were investigated by the precision impedance analyzer, thermal gravimetric analyzer, differential scanning calorimetry, and universal tester, respectively. The electrical conductivity of m-TRG/PEEK composites was greatly improved by incorporating graphene, resulting in a sharp transition from electrical insulator to semiconductor with a low percolation threshold of 0.76 vol.%. A high electrical conductivity of 0.18 S m^?1 was achieved with 3.84 vol.% of m-TRG. The data were compared with those of composites reduced chemically, and the results showed that thermal reduction was an effective method to acquire higher electrical conductive composites. The excellent electrical property should be attributed to the large specific surface area of m-TRG, well dispersion of m-TRG in PEEK matrix, and good compatibility of m-TRG with PEEK matrix, as proven by scanning electron microscope. Besides, m-TRG/PEEK composites also exhibited relatively good thermal and mechanical properties.     

NEXAFS study of multi-walled carbon nanotubes functionalization with sulfonated poly(ether ether ketone) chains

Functionalization of multi-walled carbon nanotubes (MWNTs) surface by sulfonated poly (ether ether ketone) SPEEK chains using a direct attachment reaction was investigated. A two step method was performed. MWNTs were oxidized by a nitric acid treatment to generate carboxyl groups on their surface. The grafting reaction of sulfonated groups of SPEEK with carboxyl groups present on the surface of oxidized MWNTs readily proceeds by using hexane diamine as an interlinking molecule. Transmission electron microscopy (TEM) shows that tubes are wrapped by polymer chains. Near edge X-ray absorption fine structure spectroscopy (NEXAFS) at the C K-edge, O K-edge, and N K-edge and X-ray photoelectron spectroscopy (XPS) were used to give evidence of covalent functionalization of MWNTs by SPEEK macromolecules.     

The fracture behaviour of carbon fibre reinforced poly(ether etherketone)

A comprehensive series of experiments is reported on the propagation of cracks in samples of uniaxially aligned continuous carbon-fibre-reinforced poly(ether etherketone) made by laying up preimpregnated tapes. Two different double cantilever beam specimens have been studied involving propagation of cracks parallel to the fibre direction on planes parallel to and perpendicular to the plane of the tapes. Bend tests have also been performed, both quasistatic and under impact loading. The results were analysed using anisotropic linear elastic fracture mechanics and values for the critical stress intensity factor and critical strain energy release rate have been obtained from each type of test with good internal consistency. The importance of toughening mechanisms based on matrix ductility, fibre bridging between fracture surfaces and fibre breakage is discussed quantitatively.     

Impact–fatigue behaviour of unidirectional carbon fibre reinforced polyetherimide (PEI) composites

Impact fatigue properties of unidirectional carbon fibre-reinforced polyetherimide (PEI) composites was evaluated by subjecting standard izod impact samples to low velocity impact loading at energy levels ranging 0.16–1.08 J by using Ceast Model Resil 25, a pendulum type instrumented impact test system. The effect of the previous low velocity impacts on the impact properties of the laminates was investigated. On the other hand materials were subjected to repeated low velocity impact tests up to fracture. Results of repeated impact study are reported in terms of peak load, absorbed energy and number of impacts. Fractographic analysis revealed the fracture by primary debonding, with fibre breakage and pullout in the tensile zone, but a shear fracture of fibre bundles in the compressive zone of the specimen.     

聚醚醚酮和烯丙基化合物改性双马来酰亚胺复合材料微观结构及力学性能

采用浓H₂SO₄氧化聚醚醚酮（PEEK）得到磺化聚醚醚酮（SPEEK）,以3,3'-二烯丙基双酚A （BBA）、双酚A双烯丙基醚（BBE）为活性稀释剂、SPEEK为改性剂、双马来酰亚胺（BMI）树脂为基体,浇注成型制备SPEEK/BBA-BBE-BMI复合材料,同时研究了SPEEK的改性效果及复合材料微观形貌与力学性能。结果表明：SPEEK改性效果较好,在FTIR中存在明显的磺酸基团特征峰,SEM和能谱分析表明,SPEEK微观形貌变化明显,硫元素含量较高;SPEEK/BBA-BBE-BMI复合材料的微观形貌显示,SPEEK在基体中呈现直径为2 μm左右的多孔状两相结构,且分散均匀,此多孔结构改善了复合材料的断裂形貌,由脆性断裂转变为韧性断裂,当断裂纹遇到SPEEK组分时受阻而出现不规则发散,此变化会赋予复合材料更加优异的性能。力学性能测试结果显示,当SPEEK含量为5wt%时,SPEEK/BBA-BBE-BMI复合材料的弯曲强度和冲击强度达到最佳,分别为147.93 MPa和15.74 kJ/mm²,分别比基体提高了49.47%和66.21%。     

The effects of solvent sorption on the properties of poly(ether ether ketone)

A study has been carried out on the sorption of ortho-dichlorobenzene, N,N-dimethylformamide and water by poly(ether ether ketone) (PEEK). Two types of PEEK samples have been analysed; the first in the amorphous state and the second with a high crystallinity level. The sorption and desorption curves have been determined and the effect of the solvent presence on the mechanical properties has been analysed by means of the tensile test. PEEK is affected to a different extent by the solvents studied and also by the crystallinity of the polymer. Sorption takes place only in the case of amorphous PEEK. Its effect on the mechanical properties of PEEK is explained on the basis of the two concomitant processes that are the consequence of sorption, these are: plasticization and induced crystallization.     

磺化聚醚砜上浆剂对碳纤维/聚醚砜复合材料界面性能的影响

为了提高碳纤维(CFs)增强热塑性树脂聚醚砜(PES)复合材料的界面结合力,对PES进行磺化改性,得到磺酸基聚醚砜(SPES)制备的CFs上浆剂,研究了SPES上浆剂对CFs/PES复合材料界面性能的影响和上浆剂质量分数对CFs/PES复合材料的作用效果。结果表明:经过SPES上浆的纤维毛丝量降低、耐磨性提高。同时FTIR和XPS分析表明:SPES中的—SO3H基团与CFs表面微量的活性官能团发生了化学反应,提高了增强体CFs与基体树脂PES间的黏连。当上浆剂含量为1wt%时,CFs/PES复合材料的层间剪切强度(ILSS)提高最显著,比未上浆改性的CFs/PES复合材料的提高了24%。SEM照片证实在此浓度下CFs与PES结合更加紧密。动态力学热分析(DMTA)结果亦证明1wt%的SPES上浆剂提高了CFs/PES复合材料的玻璃化转变温度。     

聚乙二醇丙烯酸酯表面改性聚醚砜酮微孔膜的结构和性能

为了提高聚醚砜酮(PPESK)微孔膜的亲水性和抗污性,采用紫外(UV)辐照引发聚乙二醇丙烯酸酯(PEGA)在膜上发生接枝和交联,在膜表面形成稳定的亲水层.利用场发射扫描电镜(SEM)研究了固定PEGA后PPESK膜表面形貌的变化.表面改性后PPESK膜的水接触角的降低表明PEGA的固定有利于提高其亲水性,蛋白质静态吸附实验显示膜的抗蛋白质污染能力增强,渗透实验表明膜表面较低数量的PEGA亲水链有利于提高PPESK微孔膜的水通量,膜的溶质截留率增大,截留分子量(MWCO)减小.     

Effect of water immersion on the interlaminar and flexural performance of low cost liquid resin infused carbon fabric composites

This study investigates some potential benefits of using non-epoxy matrices in carbon fibre composites, targeting specific marine and wind energy applications. Water uptake during and after immersion for up to 28 days in deionised water at 40 °C, and the effects of such conditioning on the interlaminar shear and flexural performance of the composites with isophthalic polyester, vinyl ester and urethane acrylate matrices were compared to those of equivalent composites impregnated with three grades of epoxy resin. Results demonstrated that, although the epoxy systems perform equally or better than the alternative resins in the dry state, they are also more sensitive to property degradation due to water ingress. The relatively lower water absorption and subsequent limited reduction in performance of vinyl ester and urethane acrylate composites is sufficiently promising to justify further study.