Carbon-nanofibre-reinforced poly(ether ether ketone) fibres

Nano-reinforced fibres were spun from a semicrystalline high-performance poly(ether ether ketone) containing up to 10 wt% vapour-grown carbon nanofibres using conventional polymer processing equipment. Mechanical tensile testing revealed increases in nanocomposite stiffness, yield stress, and fracture strength for both as-spun and heat-treated fibres. X-ray and differential scanning calorimetry analyses were performed in order to investigate both the orientation of nanofibres within the polymer matrix and the matrix morphology. The carbon nanofibres were found to be well aligned with the direction of flow during processing. Significantly, the degree of crystallinity of the poly(ether ether ketone) matrix was found to increase with the initial addition of nanofibres although the crystal structure was not affected. The measured increase in composite tensile modulus is compared to injection-moulded nanocomposite samples made from the same blends. The results highlight the need to characterise the matrix morphology when evaluating nanocomposite performance and hence deducing the intrinsic properties of the nanoscale reinforcement.     

Phase behaviour and mechanical properties of poly(ether ether ketone)-poly(ether sulphone) blends

The phase behaviour and the mechanical properties of binary blends composed of poly(ether ether ketone) and poly(ether sulphone) have been studied both in the amorphous state and after crystallization of poly(ether ether ketone).Differential scanning calorimetry and dynamical mechanical analysis clearly show the existence of phase separation in the blends. Density measurements confirm the absence of strong interactions between the blend components, as well as the slight effect of PES on the crystallization of PEEK.The mechanical properties of the quenched, amorphous blends remain surprisingly good in spite of the observed immiscibility, however, slowly cooled, crystalline blends appear as brittle materials.     

Thin film and bulk deformation behaviour of poly(ether ether ketone)/poly(ether imide) blends

The deformation behaviour of amorphous thin films of poly(ether ether ketone) (PEEK)/poly(ether imide) (PEI) blends was investigated over a wide temperature range by optical and transmission electron microscopy. All the materials showed localized shear deformation at temperatures well below Tg. In pure PEI and in blends with up to 60 wt% PEEK content, a transition from shear deformation to disentanglement crazing occurred as the temperature was raised. However, this transition was absent in PEEK, which deformed by shear over the whole temperature range, and similar behaviour was found for PEI/80 wt% PEEK. It is argued that at high PEEK content disentanglement crazing is suppressed by strain-induced crystallization and some evidence for crystalline order in deformed regions of initially amorphous PEEK thin films was obtained by electron diffraction. The thin film deformation behaviour of the blends was also shown to be consistent with their bulk deformation behaviour, a high temperature ductile–brittle transition being observed at low PEEK content in tensile tests. This revised version was published online in November 2006 with corrections to the Cover Date.     

含有叔胺结构的聚醚醚酮单体的合成

通过三步反应合成了一种具有叔胺结构的聚醚醚酮单体,其结构经1H NMR1、3CNMR、IR和元素分析确证,同时讨论了影响反应的因素。     

Preparation of nanosilver particles into sulfonated poly(ether ether ketone) (S-PEEK) nanostructures by electrospinning

By using the interaction between the sulfonated groups and silver ions, nanosilver particles were successfully introduced into S-PEEK nanostructures (nanospheres and nanofibers) by electrospinning. The nanoparticles were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectra (XPS), UV/vis, etc. The size of the spheres increases with the weight concentration of silver exchanged sulfonated poly(ether ether ketone) (S-PEEK-Ag) increasing. The size of the silver particles can be controlled by adjusting the sulfonated degree (number of sulfonate groups per repeating unit) of sulfonated poly(ether ether ketone) (S-PEEK) and the weight ratio of the S-PEEK solutions. This paper provides a new method for the preparation of nanometal particles into nanostructures.     

Synthesis and characterization of poly(ether sulfone ether ketone ketone) grafted poly(sulfopropyl methacrylate) for proton exchange membranes via atom transfer radical polymerization

A series of copolymers of poly(ether sulfone ether ketone ketone) grafted poly(sulfopropyl methacrylate) (PESEKK-g-PSPMA) were successfully synthesized by atom transfer radical polymerization (ATRP) of sulfopropyl methacrylate (SPMA) after chloromethylation of poly(ether sulfone ether ketone ketone) (PESEKK) backbone. The structure of the chloromethyl PESEKK and the copolymers were carefully investigated. Variation of the polymerization time leads to the formation of copolymers with different degree of sulfonation (DS). The properties of the proton exchange membranes such as water uptake, ion exchange capacity, proton conductivity, and methanol permeability are studied with compared to those of Nafion 117 membranes and could be modulated simply by control of the ATRP time. The copolymers exhibited much lower methanol permeability and higher proton conductivity as compared with Nafion 117.     

酚酞基聚醚砜溶解度参数的测定

采用浊度滴定法测定和基团贡献法估算了酚酞基聚醚砜的溶解度参数。基团贡献法估算与浊度滴定法测定的结果相吻合。测得酚酞基聚醚砜的溶解度参数为20.76J1/2mL-1/2,这对研究其溶液性质和应用有重要的意义。     

聚醚醚酮增韧改性环氧树脂

采用共混法用聚醚醚酮(PEEK)改性环氧树脂(EP),借助差示扫描量热分析(DSC)确定了环氧树脂的固化工艺,测试了共混体系的工艺性能,研究了聚醚醚酮含量对环氧树脂力学性能的影响。借助扫描电子显微镜(SEM)对材料断裂面的形态结构进行了分析,探讨了体系的形态结构与冲击性能之间的关系。结果表明,在改性材料的韧性有所提高的同时,压缩强度、马丁耐热都没有降低。从断裂面的形态来看,是属于韧性断裂。当PEEK的加入量为6%时,韧性最好,达到19．1kJ/m~2,比纯的环氧树脂增加了107．6%。     

聚醚醚酮增韧改性环氧树脂

采用共混法用聚醚醚酮(PEEK)改性环氧树脂(EP),借助差示扫描量热分析(DSC)确定了环氧树脂的固化工艺,测试了共混体系的工艺性能,研究了聚醚醚酮含量对环氧树脂力学性能的影响.借助扫描电子显微镜(SEM)对材料断裂面的形态结构进行了分析,探讨了体系的形态结构与冲击性能之间的关系.结果表明,在改性材料的韧性有所提高的同时,压缩强度、马丁耐热都没有降低.从断裂面的形态来看,是属于韧性断裂.当PEEK的加入量为6%时,韧性最好,达到19.1 kJ/m2,比纯的环氧树脂增加了107.6%.     

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.     

新型杂萘联苯聚芳醚腈(酮)耐高温绝缘漆的研制

系统地研究了杂萘联苯PPEN（K）聚合物在绝缘漆领域的应用,考察了PPENK中腈、酮含量对绝缘漆性能的影响,发现当N／K=1／1时,绝缘漆具有优异的机械性能;对比了PPENK、PPENKK、PPEN和PPEN—BPA几种聚合物所制备的绝缘漆的性能,认为以PPENK树脂为主要成膜物制得的绝缘漆综合性能最优;在此基础上,选择适当的涂线工艺,成功地研制出了新型PPENK漆包线,其机械性能、电性能和热性能都远远高于220级聚酰亚胺漆包线国家标准要求。     

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.     

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...     

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%。     

Thermally stimulated depolarization of poly(ether block amide) copolymer

Phase segregation in poly(ether block amide) copolymer has been studied by thermally stimulated depolarization (TSD). Well-defined, complex and partial phase segregation were observed depending on the molecular mass of each segment of the copolymer. A new glass transition peak appeared were broadened. Soft-segment component poly(tetramethylene glycol) (PTMG), with a lower molecular mass, was found to be completely amorphous. No additional Maxwell-Wagner-Sillers (MWS) effect peak at the phase boundaries was detected.     

Preparation and characterization of poly (methyl methacrylate) and sulfonated poly (ether ether ketone) blend ultrafiltration membranes for protein separation applications

Poly (methyl methacrylate) (PMMA) and poly (methyl methacrylate)/sulfonated poly (ether ether ketone) (SPEEK) blend membranes were prepared by phase inversion technique in various composition using N,N'-dimethylformamide as solvent. The prepared membranes were characterized in terms of pure water flux, water content, porosity and thermal stability. The addition of SPEEK to the casting solution resulted in membranes with high pure water flux, water content, porosity and slightly low thermal stability. The cross sectional views of the blend membranes under electron microscope confirm the porosity and water flux results. The effect of the addition of SPEEK into the PMMA matrix on the extent of bovine serum albumin (BSA) separation was studied. It was found that the permeate flux increased significantly while the rejection of BSA from aqueous solution reduced moderately during ultrafiltration (UF) process. The effect was attributed to the increase in porosity and charge of the membrane due to the addition of SPEEK into the PMMA blend solution.     

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.     

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。     

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 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.