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发泡剂粒径对硅橡胶泡沫材料性能的影响研究 总被引:2,自引:0,他引:2
以硅橡胶为基体材料,采用发泡剂H制备硅泡沫材料.研究了不同发泡助剂对发泡剂H分解温度的影响,以及发泡剂粒径对硅泡沫材料密度、硬度、力学性能、压缩性能和泡孔大小及其分布状态的影响规律.结果表明:发泡剂H与发泡助剂尿素的比例为1:1时,两者之间具有良好的匹配性;在发泡剂粒径对硅泡沫材料性能的影响方面,随着发泡剂粒径的减小,硅泡沫材料的密度、硬度、拉伸强度和40%压缩应变下的压缩应力值逐渐变大,当发泡剂粒径达到300目时,上述性能参数达到最大值,之后又出现下降趋势;其中,原始目数和较大目数下制备的硅泡沫材料的性能变化情况相似.同时,采用SEM技术对不同发泡剂粒径时硅泡沫材料的泡孔大小和分布状态进行了分析. 相似文献
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以超临界二氧化碳为物理发泡剂,制备出一种具有良好导电性能的硅橡胶/碳纳米管/炭黑多相复合泡沫材料。系统研究了不同碳纳米管含量及不同加工参数对硅橡胶发泡行为和最终硅橡胶泡沫材料导电性能的影响。实验结果表明,碳纳米管和炭黑在硅橡胶基体中分散良好,无明显团聚体出现。均匀分散的碳纳米管能够提高发泡时的成核密度,从而得到具有较小泡孔尺寸和较高泡孔密度的泡沫材料。研究发现随着饱和温度升高,泡孔尺寸变大,泡孔合并现象明显;随饱和压力增加,泡孔尺寸变小,泡孔密度增加,泡孔合并现象减少。不同泡孔形态对应其导电性能也有所不同,当泡孔尺寸较小,泡孔分布均匀的泡沫材料导电性能较好。 相似文献
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在空间质子辐照下甲基硅橡胶的破坏模型 总被引:2,自引:0,他引:2
利用空间辐照环境地面模拟设备研究了质子辐照对甲基硅橡胶的破坏,建立了甲基硅橡胶的破坏模型.结果表明,在辐照能量为180 keV,辐照剂量为1016cm-2的条件下,被质子辐照后,硅橡胶生成CH3SiOCH3气体产物;量子化学计算表明,在H 直接进攻硅橡胶高分子链中的O导致高分子链断裂的过程中要放热655.34 kJ/mol,是唯一的放热反应通道.这一过程不会形成稳定的过渡态和中间体,而是直接形成断键产物.计算结果与质子辐照生成的气体产物CH3SiOCH3一致. 相似文献
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《International Journal of Impact Engineering》2006,32(9):1384-1402
The uniaxial compressive responses of silicone rubber (B452 and Sil8800) and pig skin have been measured over a wide range of strain rates (0.004–4000 s−1). The uniaxial tensile response of the silicone rubbers was also measured at low strain rates. The high strain rate compression tests were performed using a split-Hopkinson pressure bar made from AZM magnesium alloy. High gain semi-conductor strain gauges were used to detect the low levels of stress (1–10 MPa), and a pulse shaper increased the rise time of dynamic loading on the specimen. The experiments reveal that pig skin strain hardens more rapidly than silicone rubbers and has a greater strain rate sensitivity: pig skin stiffens and strengthens with increasing strain rate over the full range explored, whereas silicone rubber stiffens and strengthens at strain rates in excess of 40 s−1. A one term Ogden strain energy density function adequately describes the measured constitutive response of each solid, and a strategy is outlined for determining the associated material constants (strain hardening exponent and a shear modulus). The strain rate sensitivities of the pig skin and two silicone rubbers are each quantified by an increase in the shear modulus with increasing strain rate, with no attendant change in the strain hardening exponent. It is shown that the Mooney-Rivlin model is unable to describe the strong strain hardening capacity of these rubber-like solids. 相似文献
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以天然绢云母矿物为原料,利用气流磨超细粉碎、乙烯基三乙氧基硅烷表面修饰处理对绢云母进行深加工,得到有机化的绢云母超细粉体,再采用溶液聚合方法制备出具有优良性能的超细绢云母/加成型液体硅橡胶复合材料。用SEM对其微观形貌进行了观察和分析,通过观察SEM可以发现经偶联剂表面修饰处理后超细绢云母在硅橡胶基体中分散均匀。当超细绢云母质量分数为8%时,复合材料的拉伸强度和邵氏硬度达到了1.25 MPa和61,分别比纯硅橡胶提高了197.62%和48.78%。TGA测试结果表明,超细绢云母可显著提高硅橡胶的热稳定性能。此外,用Kraus方程对超细绢云母与硅橡胶之间的相互作用进行了表征。 相似文献
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Silicone rubber composed of diverse vinyl content silicone gums blending were prepared and their mechanical properties were investigated. The silicone rubber composed of diverse vinyl content silicone gums blending whose crosslinking points were concentration distribution exhibited better tearing strength and higher tensile modulus in comparison with single vinyl content gums which were mean distribution. The average molecular weight (Mc) of the silicone rubber composed of diverse vinyl content blending are lower than that of single vinyl molar content 0.16% which was calculated by swelling equilibrium method. The viscoelastic behavior indicated the silicone rubber composed of 0.04% and 0.3% vinyl molar content gums blending possessed perfect flexibility at low temperature because it had the lowest glass transition temperature (Tg), and this sample had the largest storage modulus and loss modulus. 相似文献
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为获得一种低压缩、永久变形及高回弹的导电屏蔽硅橡胶密封材料,以经偶联剂表面处理的炭黑作补强剂及导电填料,乙烯基硅橡胶生胶作基料,制备出一种导电炭黑/硅橡胶复合材料。研究了不同炭黑含量的导电炭黑/硅橡胶复合材料的力学性能、弹性、分散性以及电性能,采用SEM观察了炭黑在硅橡胶基体中的分布形貌,分析了导电炭黑/硅橡胶复合材料的导电机制及屏蔽机制。结果表明:随着炭黑含量的增加,导电炭黑/硅橡胶复合材料的Shore A硬度由31增至70;拉伸强度先由3.31 MPa增至5.28 MPa,而后趋于稳定;拉断伸长率先由198%增至297%,然后再减小至210%;恒定压缩永久变形量先减小后增大,瞬间回弹率逐渐减小;由于"炭黑簇"的形成及导电通路的完善,导电炭黑/硅橡胶复合材料的导电性能及屏蔽效能增强。 相似文献
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采用交联改性的方法对较低分子量的乙烯基硅橡胶进行了改性研究,制备了高通量的富氧膜,结合单因素实验法和Design-expert正交实验设计,考察了原料配比、交联反应时间、固化温度和固化时间等因素对富氧膜性能的影响,确定了最佳富氧性能膜的制备条件:原料配比4.3,反应时间2.15h,固化温度86.25℃,固化时间1.75h;获得了富氧浓度为28.68%,透气量为4696.33 barrer的富氧膜,该膜的富氧浓度与常规商品化膜相当,透气量为常规商品化膜的2~4倍,有应用于发动机富氧进气系统的前景。通过扫描电镜检测、机械性能检测等手段对复合膜进行了进一步表征。 相似文献