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61.
连续碳纤维增强的聚芳醚酮复合材料的层间破坏 总被引:3,自引:2,他引:3
用双悬臂梁和端开口弯曲试件分别研究了连续碳纤维增强的聚芳醚酮复合材料(CF/PEK-C)的Ⅰ型和Ⅱ型的层间破坏。CF/PEK-C的Ⅰ型层破坏的线弹性断裂判据G_(Ⅰc)和弹塑性断裂判据J_(Ⅰc)分别为0.69KJ/m~2且与裂纹长度无关。CF/PEK-C的Ⅱ型层间破坏的稳定性,与裂纹和半距之比α/L有关。当α/L小于0.7时,表现为不稳定的Ⅱ型层间破坏的断裂韧性G_(Ⅱc)为1.62KJ/m~2。当α/L大于0.7时,则为稳定的Ⅱ型层间破坏。此时的G_(Ⅱc)与临界点的选择有关。由亚临界点和0.95点法得出的G_(Ⅱc)值分别为1.73和2.74KJ.M~2。 相似文献
62.
The composite material of polyaniline/NiO/sodium dodecylbenzenesulfonate (SDBS) is synthesized in SDBS micelles. The composite material has satisfactory conductivity and thermostability, and the particle length, width, and thickness are about 200–500 m, 3–5 m, and 40–96 nm, respectively. 相似文献
63.
具有自修复能力的聚合物材料 总被引:4,自引:0,他引:4
各项性能已经达到工程材料指标要求的聚合物材料,在使用过程中不可避免地会产生裂纹,进而在使用过程中包藏着隐患,直至丧失使用价值。裂纹的早期修复,特别是自修复是一个现实而重要的问题。本文介绍了两类修复机制,即共价键与非共价键愈合,重点分析了近年来按共价键机理愈合、具有自修复能力的聚合物材料的研究成果、优缺点及发展前景。 相似文献
64.
65.
A new ion exchange membrane based on polyvinylidene fluoride (PVDF) and sulfonated poly(styrene-
divinylbenzene) was prepared by in-situ polymerization. The incorporation of sulfonic groups into the polyvinylidene fluoride composite membrane was confirmed by infrared spectroscopy (IR), ion exchange capacity (IEC) and energy dispersive X-ray analysis (EDAX). Area resistance, IEC and water uptake of the treated membrane were evaluated. When 20% of the crosslinked membrane was sulfonated at 80°C for 22 h, the PVDF ion exchange membrane can attain 0.8 Ω·cm2area resistance in NaCl aqueous solution at 25℃, IEC is as high as 2.43 millimoles per gram of the wet membrane. The
hydrophilicity of PVDF membrane is also significantly improved after treatment. When 60% of crosslinked membrane was sulfonated at 80 ℃ for 6 h, water uptake of the treated membrane can attain 64.7%. 相似文献
66.
Fine particle superacidic sulfated zirconia (SO42−/ZrO2, S-ZrO2) was synthesized by ameliorated method, and composite membranes with different S-ZrO2 contents were prepared by a recasting procedure from a suspension of S-ZrO2 powder and Nafion solution. The physico-chemical properties of the membranes were studied by ion exchange capacity (IEC) and liquid water uptake measurements, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, thermogravimetry–mass spectrometry (TG–MS) and Fourier transform infrared (FT-IR) spectroscopy. The results showed that the IEC of composite membrane increased with the content of S-ZrO2, S-ZrO2 was compatible with the Nafion matrix, the incorporation of the S-ZrO2 could increase the crystallinity and also improve the initial degradation temperature of the composite membrane. The performance of single cell was the best when the S-ZrO2 content was 15 wt.%, and achieved 1.35 W/cm2 at 80 °C and 0.99 W/cm2 at 120 °C based on H2/O2 and at a pressure of 2 atm, the performance of the single cell with optimized S-ZrO2 was far more than that of the Nafion at the same condition (e.g. 1.28 W/cm2 at 80 °C, 0.75 W/cm2 at 120 °C). The 15 wt.% S-ZrO2/Nafion composite membrane showed lower fuel cell internal resistance than Nafion membranes at high temperature and low relative humidity (RH). 相似文献
67.
Donghui Wang Zhengping Hao Daiyun Cheng Xicheng Shi Chun Hu 《Journal of molecular catalysis. A, Chemical》2003,200(1-2):229-238
Composite oxide MOx/Al2O3 supported gold catalysts for low-temperature CO oxidation were prepared and investigated. The presence of transition metal oxide was proved to be beneficial to the improvement of catalytic performance of Au/Al2O3 catalysts for low-temperature CO oxidation. Furthermore, the influence of various pretreatment conditions on Au/MOx/Al2O3 catalysts was studied carefully. The image of TEM showed that gold catalyst with small gold particles only in the form of a fine dispersion exhibited highly catalytic activity. The XPS, Fourier transform infrared (FTIR) spectroscopy characterization results of Au/FeOx/Al2O3 catalyst showed that gold catalysts having partially oxidized gold species have the best catalytic performance. One possible pathway for CO oxidation on Au/FeOx/Al2O3 catalyst is that the CO adsorbed on gold particles reacts with adsorbed oxygen, which is possible to occur on oxygen vacancies on the support or at the metal–support interface. 相似文献
68.
69.
《Electroanalysis》2003,15(21):1719-1722
Composite‐electroplating of zinc particles with polytetrafluoroethylene at a zinc substrate resulted in a working electrode which could be used at high negative potentials (to ?2.5 V vs. Ag/AgCl) without significant hydrogen evolution. The electrodes were characterized by SEM and CV and were used to detect organochloride compounds in a water‐acetonitrile mixture, by potential step methods. 相似文献
70.
Aiming to develop a high performance fiber reinforced rubber of SBR, a special technique using electron beam (EB) irradiation-induced graft-polymerization was applied to ultra-high molecular-weight polyethylene (UHMWPE) fibers. Although UHMWPE is chemically inert, N-vinyl formamide (NVF) could be graft-polymerized onto the UHMWPE fiber surface with this special technique. A maximum grafting percentage of 23.6% was achieved. The composite of SBR and grafted UHMWPE fibers with maximum grafting indicated a linear increase in the initial modulus and strength with the fiber content. At the fiber content of 10%, the initial modulus was improved about five times with respect to that of the pure SBR, while the strength was done about twice. At this moment, only a small reduction could be observed in the strain compared with that of pure SBR. The fiber reinforced rubber with a good performance was obtained in the system of SBR and grafted UHMWPE fibers. 相似文献