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A kind of chemical method that used water as the liquid reaction medium to decompose epoxy resin was studied. The thermosetting epoxy resin was decomposed successfully under the condition of near-critical water. The decomposition rate of epoxy resin raised rapidly as the reaction time and reaction temperature increased. The decomposition reaction products were characterized by infra-red spectra and gas chromatography-mass spectrometry. The phenol, isopropylphenol, 4, 4′-(1-methylethylidene) bis-phenol were found as the main compounds in liquid products, which were common monomers from epoxy resin. When reaction was carried out at the temperature of 260 °C–300 °C, the decomposition mechanism of epoxy resin was envisaged as the ether and ester bonds cracking. 相似文献
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综述了断裂力学方法在橡胶复合材料中的应用现状,着重介绍了撕裂能理论在预测疲劳裂纹增长速率以及预报疲劳寿命方面的应用。 相似文献
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以单向帘线增强橡胶复合材料为研究对象,研究了周期载荷作用下橡胶复合材料的热生成对疲劳行为的影响。橡胶复合材料在疲劳过程中伴随较多的热生成,SEM观察表明:热生成温度与断裂表面密切联系。橡胶复合材料的滞后损失并不是全部转换为热,而是其中一部分被内能变化所消耗,不转换为有效热生成的滞后损失与疲劳损伤导致的结构变化有关。在疲劳试验中,直到疲劳破坏所消耗的平均有效能耗与疲劳寿命之间存在定量关系。 相似文献
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针对近年来出现的较严重的海上溢油污染事故,分析了海上石油污染的原因及其治理措施,介绍了凝油剂的应用现状。对处理水中溢油较有前景的凝油剂,尤其是相选择性超分子凝油剂的研究现状进行了综述;主要介绍了糖类衍生型、氨基酸衍生型、胆甾衍生型和有机酸及其盐衍生型相选择性超分子凝油剂,指出了它们在制备新型低价、高效、环保、可重复利用凝油剂方面的巨大潜力。开发使用简单、室温下能快速胶凝溢油、形成凝油块强度高的相选择性超分子凝油剂,或将凝油剂和吸油剂相结合是将来的发展方向。 相似文献
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利用自行建立的疲劳试验系统,以单向聚酯/橡胶复合材料和人造丝/橡胶复合材料为研究对象,揭示了在周期载荷作用下橡胶复合材料的疲劳损伤累积特性,给出了疲劳寿命预报方程,研究了频率对像复合材料疲劳寿命的影响以及材料表面温度的变化规律。发现:橡胶复合材料疲劳过程中伴有较高的热生成,这是橡胶复合材料与其他脆性复合材料最大的不同。疲劳过程中,聚酯/橡胶复合材料的表面温度可达100℃,人造丝/橡胶复合材料的表面温度可达40℃。频率对不同橡胶复合材料的疲劳寿命具有不同的影响。对滞后损失较大的聚酯/橡胶复合材料,增加频率其疲劳寿命明显降低;而对于滞后损失较小的人造丝/像胶复合材料,频率对其疲劳寿命的影响不明显。 相似文献
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利用自建的试验系统,采用单向聚酯帘线/橡胶复合材料模拟汽车子午胎的胎体,研究了疲劳载荷下橡胶复合材料的变形和损伤累积特性,讨论了两徊加载方式对疲劳性能的影响,结果表明:定载荷疲劳测试优于伸长疲劳测试,为评价轮胎的疲劳特性,预报轮胎的疲劳寿命提供了有效手段。 相似文献
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This study aimed to investigate the effect of artificial weathering test on the photoaging behavior of TPU films. Changes in mechanical properties, morphology and chemical structures are studied by tensile test, scanning electron microscopy, atomic force microscopy, Fourier-transformed infrared, and X-ray photoelectron spectroscopy. The results show that the photoaging negatively affects the initial modulus and stress at break values of TPU films. The surface of the specimen that is exposed to irradiation becomes rough, and some visible micro-defects such as blisters and voids can be detected. The morphology of the fracture surfaces illustrates that irradiation reduces the plasticity but increases the brittleness of the TPU films. The chemical structure analyses of the accelerated aged films prove that chemical structural changes in TPU films occur. The irradiation may break the long molecular chains on the surface of the specimens and form the lowmolecular weight oxygen-containing groups. The number of chain scissions increases with the increase in exposure time. 相似文献
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