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81.
T. Cotgreave 《Polymer》1985,26(9):1419-1422
A milled fibre reinforced epoxy resin composite (MFRE) has been developed for low temperature use. It is resistant to fracture at temperatures down to at least 77 K in direct contact with liquefied gases. It can be used as an adhesive, a gap-filling mastic or a moulding compound for difficult cryogenic applications. The characteristics of the material and some applications are described. 相似文献
82.
83.
新型丙烯-乙烯共聚物增韧聚丙烯的研究 总被引:1,自引:0,他引:1
丙烯-乙烯共聚物Vistamaxx(VM)是一种丙烯摩尔含量占70%以上的新型弹性体。用VM增韧聚丙烯(PP),考察了PP/VM共混物的力学性能、微观形态结构以及结晶性能,并与乙烯-辛烯共聚物(POE)与PP的共混体系进行了对比。结果表明,常温下VM增韧效果优于POE,PP/VM体系拉伸性能优于PP/POE体系;VM在PP中表现出比POE更好的分散性;VM具有与PP相同的晶型,VM的加入细化了PP的晶粒。 相似文献
84.
W.Wade Adams Robert M. Briber Edward S. Sherman Roger S. Porter Edwin L. Thomas 《Polymer》1985,26(1):17-26
The microstructure of a series of solid state extruded polyethylene fibres was examined by wide- and small-angle X-ray scattering. By measuring absolute intensities using a two dimensional position sensitive detector, accurate values of the small-angle invariant for anisotropic samples were obtained. This measurement coupled with wide-angle X-ray scattering and d.s.c. permitted determination of the density of the noncrystalline component. The use of a two phase model for solid state extruded polyethylene is justified if consideration is given to the effective densities of the crystalline and noncrystalline phases, which change with deformation. The effective density of the crystalline phase decreases by 1% (0.999–0.990 g cm?3) from the unextruded billet compared to a 36 draw ratio extrudate, while the noncrystalline phase density increases by 6% (0.84–0.89 g cm?3). These changes lead to an overall decrease in the mean squared electron density fluctuation of 63%. The average axial crystallite length measured by wide-angle X-ray scattering increases with extrusion draw ratio while the SAXS long period decreases and weakens considerably. These observations and the electron microscopy results from the previous paper, (Polymer, 1982, 23, 1069), are fully consistent with the key features of the Peterlin model of fibre microstructure. 相似文献
85.
K2ZrF6助浸SiC涂层碳纤维增强Al复合材料的研究 总被引:1,自引:0,他引:1
研究了用K_2ZrF_6助浸法制造C/Al复合材料的工艺和K_2ZrF_6的助浸机理结果表明:K_2ZrF_6处理后,C,Al间的润湿性仍比SiC,Al间的差C,Al间的润湿主要靠大量的界面化学反应、这使得复合材料的制造十分困难;而SiC、Al间的润湿靠微量的SiC在Al中的溶解K在纤维或涂层中的扩散也可能起助浸作用Al液在极短时间内对SiC涂层后的纤维束或纤维预制件浸渍良好同时,将基体Si合金化后,获得了完整的CF/SiC/Al界面,圆满解决了C/Al复合材料的界面相容性和制造中的问题 相似文献
86.
H. -Y. Nie M. J. Walzak N. S. McIntyre 《Journal of Materials Engineering and Performance》2004,13(4):451-460
Atomic force microscopy (AFM) uses a very sharp pointed mechanical probe to collect real-space morphological information of
solid surfaces. AFM was used in this study to image the surface morphology of a biaxially oriented polypropylene film. The
polymer film is characterized by a nanometer-scale, fiberlike network structure, which reflects the drawing process used during
the fabrication of the film. AFM was used to study polymer-surface treatment to improve wettability by exposing the polymer
to ozone with or without ultraviolet (UV) irradiation. Surface-morphology changes observed by AFM are the result of the surface
oxidation induced by the treatment. Due to the topographic features of the polymer film, the fiberlike structure has been
used to check the performance of the AFM tip. An AFM image is a mixture of the surface morphology and the shape of the AFM
tip. Therefore, it is important to check the performance of a tip to ensure that the AFM image collected reflects the true
surface features of the sample, rather than contamination on the AFM tip. 相似文献
87.
88.
溪洛渡水电站拦河大坝为双曲拱坝,最大坝高285.5m,大坝混凝土抗裂指标要求高,为了提高混凝土的极限拉伸值、自生体积变形性能,进行外掺改性PVA纤维大坝混凝土配合比的试验研究,并在溪洛渡水电站工程成功应用。室内试验研究和对大坝混凝土的抽样检测结果表明,掺改性PVA纤维混凝土可提高28d龄期混凝土极限拉伸值10%以上,相同龄期可减少混凝土自生体积变形收缩约15×10^-6左右,有效的提高了大坝混凝土的抗裂性能指标。 相似文献
89.
The integration of piezoelectric materials onto carbon fiber (CF) can add energy harvesting and self-power sensing capabilities enabling great potential for “Internet of Things” (IoT) applications in motion tracking, environmental sensing, and personal portable electronics. Herein, a CF-based smart composite is developed by integrating piezoelectric poly(3,4-ethylenedioxythiophene) (PEDOT)/CuSCN-coated ZnO nanorods onto the CF surfaces with no detrimental effect on the mechanical properties of the composite, forming composites using two different polymer matrices: highly flexible polydimethylsiloxane (PDMS) and more rigid epoxy. The PDMS-coated piezoelectric smart composite can serve as an energy harvester and a self-powered sensor for detecting variations in impact acceleration with increasing output voltage from 1.4 to 7.6 V under impact acceleration from 0.1 to 0.4 m s−2. Using epoxy as the matrix for a CF-reinforced plastic (CFRP) device with sensing and detection functions produces a voltage varying from 0.27 to 3.53 V when impacted at acceleration from 0.1 to 0.4 m s−2, with a lower output compared to the PDMS-coated device attributed to the greater stiffness of the matrix. Finally, spatially sensitive detection is demonstrated by positioning two piezoelectric structures at different locations, which can identify the location as well as the level of the impacting force from the fabricated device. 相似文献
90.
Fatigue behaviour and modelling of talc‐filled and short glass fibre reinforced thermoplastics,including temperature and mean stress effects 下载免费PDF全文
Effects of temperature and mean stress on fatigue behaviour of talc‐filled polypropylene (PP‐T) and short glass fibre reinforced polypropylene (PP‐G), polyamide‐66 (PA66), and a blend of polyphenylene ether and polystyrene (PPE/PS) were investigated. Load‐controlled fatigue tests were conducted under positive stress ratios (R = 0.1 and 0.3) and at several temperatures (T = 23, 85 and 120 °C). Larson–Miller parameter was used and a shift factor of Arrhenius type was developed to correlate fatigue data at various temperatures. Effect of mean stress on fatigue life was significant for some of the studied materials; however, for the PPE/PS blend no effect of mean stress was observed. Modified Goodman and Walker mean stress equations were evaluated for their ability to correlate mean stress data. A general fatigue life prediction model was also used to account for the effects of mean stress, temperature, anisotropy and frequency. 相似文献