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.     

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

Poly(ether ether ketone) nanocomposites containing vapour-grown carbon nanofibres (CNF) were produced using standard polymer processing techniques. Evaluation of the mechanical composite properties revealed a linear increase in tensile stiffness and strength with nanofibre loading fractions up to 15 wt% while matrix ductility was maintained up to 10 wt%. Electron microscopy confirmed the homogeneous dispersion and alignment of nanofibres. An interpretation of the composite performance by short-fibre theory resulted in rather low intrinsic stiffness properties of the vapour-grown CNF. Differential scanning calorimetry showed that an interaction between matrix and the nanoscale filler could occur during processing. Such changes in polymer morphology due to the presence of a nanoscale filler need to be considered when evaluating the mechanical properties of such nanocomposites.     

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.     

聚醚醚酮复合材料的研究进展

复合改性是进一步提高聚醚醚酮(PEEK)使用性能、扩展其应用领域的重要途径.本文综述了PEEK在热机械性能、摩擦学性能等方面的复合改性研究进展,以及PEEK复合材料在生物假体材料领域、磺化PEEK复合材料在质子交换膜领域的应用研究进展.     

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.     

Sulphonated poly(ether ether ketone): Synthesis and characterisation

The sulphonation of commercially available PEEK in powder form (Gatone, Gharda Chemicals Limited, India) was carried out using conc. H²SO⁴ under different reaction conditions. The duration of reaction was varied from 3–5 h, polymer concentration 4–10% (w/v) and temperature 35–50C. Structural characterisation of sulphonated polymers was done by elemental analysis, FT-IR and ¹H-NMR spectroscopy. The degree of sulphonation as calculated from ¹H-NMR and elemental analysis (S-content) was found to be in the range of 50–80%. Multistep mass loss was observed in thermogravimetric traces (recorded in N² atmosphere). The first step (50–225 ± 25C) was due to loss of moisture (1–10%) and second step (250–425 ± 25C) has been attributed to volatilization of SO³ from the sulphonic group. The backbone degradation takes place above 450C. The mechanical properties and proton conductivities of various sulphonated samples was also evaluated.     

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%.     

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%。     

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.     

Synthesis of Poly(ether ether ketone)s containing tertiary amine

A functional or reactive PEEK-Poly(ether ether ketone)s containing tertiary amine was synthesized. The product was determined by ¹H NMR, ¹³C NMR, IR spectra and elemental analysis. Thermal analysis of the polymer revealed the glass-transition temperatures (T_g = 119.57 °C), a 5% weight loss in air at 386 °C. An M_n of 10.4 kD, M_w of 20.2 kD, Polydispersity of 1.95 was obtained from GPC. The Poly(ether ether ketone)s containing a tertiary amine structure can be synthesized as a scaffolds for post-polymerization reaction.     

碳纤维-AlN/聚醚醚酮复合材料的制备与性能

以聚醚醚酮(PEEK)为基体树脂、碳纤维(CF)和氮化铝(AlN)为填料,通过模压成型的方法制备了抗静电耐热型CF-AlN/PEEK复合材料。采用高阻计、导热系数测定仪、热失重、差示扫描量热仪和SEM研究了CF-AlN/PEEK复合材料的抗静电性能、热性能、力学性能以及降温速率对复合材料性能的影响,并探讨了后期热处理对力学性能的影响。结果表明:当CF和AlN的质量分数均为10%时,CF-AlN/PEEK复合材料的性能较优,其表面电阻率达到108 Ω,比PEEK的表面电阻率提高了6个数量级;导热系数为0.418 W·(m·K)-1,初始分解温度高达573℃;拉伸强度提高了40.4%;降温速率越低,复合材料的熔点越高;后期热处理会影响CF-AlN/PEEK复合材料的力学性能,在270℃下热处理2 h,其拉伸强度可达146 MPa,表明在生产过程中,加工温度是影响复合材料性能的因素之一。      

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。     

含氰侧基联苯型聚芳醚醚酮酮/芳醚醚酮酮共聚物的合成与表征

在无水AlCl3及N-甲基吡咯烷酮(NMP)/1,2-二氯乙烷(DCE)复合溶剂的存在下,将2,6-二苯氧基苯甲腈(DPOBN)与4,4’-二氯甲酰基联苯(BClBP)及对苯二甲酰氯(TPC)进行三元低温共缩聚反应,合成了一系列含氰侧基联苯型聚芳醚醚酮酮/芳醚醚酮酮共聚物。用IR、DSC、TG、WAXD及元素分析等方法对其结构和性能进行了表征。结果表明,所合成的聚合物具有预期结构且均为非晶态聚合物;其玻璃化转变温(Tg)度为180~196℃,在N2气氛中热分解5%的温度(Td)为495~508℃,具有突出的耐高温性能。     

磺化聚醚醚酮对苯并噁嗪固化动力学的影响

采用磺化聚醚醚酮(SPEEK)对苯并噁嗪(Ba)进行催化固化。通过非等温差示扫描量热仪研究SPEEK对Ba的催化固化反应影响。进一步采用Kissinger、Ozawa和Crane法对Ba/SPEEK体系的固化动力学参数进行了计算。结果表明,SPEEK可明显降低Ba的固化温度。升温速率为10℃/min,SPEEK用量为0.1%时,Ba的固化起始温度和固化峰值温度分别降低26.1℃和9.7℃。用量增加到0.5%后,催化固化效果趋于平缓。0.3%的SPEEK使Ba固化反应活化能降低12 k J/mol。     

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.     

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.