共查询到20条相似文献,搜索用时 125 毫秒
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Loft Enszer 《粘接》2006,27(5):20-20
热熔密封胶除了粘接性能好之外,还有粘接迅速、成本低、工序少等优点。而其中的有机硅热熔密封胶与其他热熔密封胶(如丁基橡胶、聚氨酯、丙烯酸酯型等)相比具有3大特点: 相似文献
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采用α,ω-二羟基聚二甲基硅氧烷和气相法白炭黑为主要原料,制备交联剂(甲基三甲氧基硅烷与甲醇反应合成)质量分数分别为2%,4%和6%的超高层建筑用有机硅密封胶,并对其拉伸粘接性能进行研究。结果表明:3种不同交联剂质量分数的有机硅密封胶的理化性能达到指标要求;在盐雾老化试验中,随着老化时间的延长,添加4%交联剂的有机硅密封胶的拉伸粘接强度及其保持率始终保持较高水平,且粘接破坏面积几乎为0;在紫外光照老化试验中,随着紫外光照时间的延长,添加4%交联剂的有机硅密封胶的拉伸剪切强度和转矩降幅相对较小;在热老化试验中,随着热老化时间的延长,添加4%交联剂的有机硅密封胶的粘度变化相对较小,且热老化温度较高(80 ℃)时撕裂强度也未大幅降低。因此,添加4%交联剂的有机硅密封胶的拉伸粘接性能较好,密封效果最佳。 相似文献
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在温度25~250℃对3类硫化体系的5种有机硅密封剂的拉伸强度、180o剥离强度和剪切强度的研究表明:随着温度的升高,5种有机硅密封剂的拉伸强度、180o剥离强度和剪切强度均不断下降,其中拉伸强度和剪切强度降低的速率递减。有机硅密封剂的高温性能变化与硫化体系类型密切相关,脱氢硫化体系HM321密封剂在25~150℃拉伸强度、剪切强度和180o剥离强度均最高,但在25~250℃拉伸强度、剪切强度和180o剥离强度保持率均最低。脱氨硫化体系XY-602S有机硅胶粘剂在232~250℃的拉伸强度和剪切强度最高,25~250℃的拉伸强度保持率也最高。 相似文献
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缩合脱氢有机硅密封剂耐密闭状态热降解研究 总被引:2,自引:0,他引:2
以含氯硅油和正硅酸乙酯为硫化剂、有机锡为催化剂,对比了缩合脱氢和脱醇型有机硅密封剂耐密闭状态热降解性能,提出了缩合脱氯型有机硅密封剂的硫化和耐密闭状态热降解的机理。实验结果表明,缩合脱氢型有机硅密封剂在250℃和300℃的高温环境下,具有良好的耐降解性能;在高温老化的初期,密封剂由于体系中的小分子氢和水等的存在,硬度下降,当老化时间超过100h后,密封剂的硬度保持不变;同时缩合脱氢型有机硅密封剂具有良好的耐热空气老化性能。 相似文献
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During the service life of structural sealant glazing (SSG) facades, the load-bearing capacity of the silicone bonds needs to be guaranteed. Laboratory tests can assess the durability of SSG-systems based on mechanical characteristics of the bond after simultaneous exposure to both climatic and mechanical loads. This article studies how the material characteristics of two common structural sealants are affected by laboratory and field exposure. Dynamic mechanical analysis (DMA) confirms a reduction in the dynamic modulus of exposed silicone samples. Results from thermogravimetric analysis, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and small-angle X-ray scattering/wide-angle X-ray scattering show differences between the two sealants and indicate no/minor changes in the composition and morphology of the laboratory and field exposed sealants. Mechanical characterization methods, such as DMA, and tensile and shear testing of the structural bond, are shown to be sensitive toward the combined climatic and mechanical loadings, and are hence suitable for studying degradation mechanisms of structural sealants. 相似文献
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Hamada Elsayed Hassan Javed Antonio G. Sabato Federico Smeacetto Enrico Bernardo 《Journal of the European Ceramic Society》2018,38(12):4245-4251
The processing of sintered ceramics is often conditioned by the debinding step. The binders may determine some defects in the final product directly, by causing some gas evolution even at an advanced state of densification, due to incomplete decomposition at low temperature, or indirectly, by offering poor adhesion between particles, so that ‘green’ compacts may be easily damaged. The present investigation is aimed at exploring a novel concept for sintered glass-ceramics, based on the adoption of a silicone polymer as reacting binder, providing an abundant ceramic residue after firing. A glass belonging to the CaO-MgO-Al2O3-SiO2 system, already studied as a sealant in solid oxide fuel cell (SOFC) planar stack design, was reproduced in form of ‘silica-defective’ variants, featuring a SiO2 content, in the overall formulation, reduced up to 15?wt%. The overall silica content was recovered by mixing powders of the new glasses with the silicone: upon firing in air, the interaction between glass powders and polymer-derived silica led to glass-ceramics with the same phase assemblage than that formed by the reference glass and with a CTE of 9.5?×?10?6 K-1. The new approach has been successfully applied to the manufacturing of glass-ceramic seals as joining materials for solid oxide cells. 相似文献