• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The Journal of Chemical Physics >The moisture outgassing kinetics of a silica reinforced polydimethylsiloxane
【24h】

The moisture outgassing kinetics of a silica reinforced polydimethylsiloxane

机译：二氧化硅增强的聚二甲基硅氧烷的除湿气动力学

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

A silica-filled polydimethylsiloxane (PDMS) composite M9787 was investigated for potential outgassing in a vacuum/dry environment with the temperature programmed desorption/reaction method. The outgassing kinetics of 463 K vacuum heat-treated samples, vacuum heat-treated samples which were subsequently re-exposed to moisture, and untreated samples were extracted using the isoconversional and constrained iterative regression methods in a complementary fashion. Density functional theory (DFT) calculations of water interactions with a silica surface were also performed to provide insight into the structural motifs leading to the obtained kinetic parameters. Kinetic analysis/model revealed that no outgassing occurs from the vacuum heat-treated samples in subsequent vacuum/dry environment applications at room temperature (similar to 300 K). The main effect of re-exposure of the vacuum heat-treated samples to a glove box condition (similar to 30 ppm by volume of H2O) for even a couple of days was the formation, on the silica surface fillers, of similar to 60 ppm by weight of physisorbed and loosely bonded moisture, which subsequently outgasses at room temperature in a vacuum/dry environment in a time span of 10 yr. However, without any vacuum heat treatment and even after 1 h of vacuum pump down, about 300 ppm by weight of H2O would be released from the PDMS in the next few hours. Thereafter the outgassing rate slows down substantially. The presented methodology of using the isoconversional kinetic analysis results and some appropriate nature of the reaction as the constraints for more accurate iterative regression analysis/deconvolution of complex kinetic spectra, and of checking the so-obtained results with first principle calculations such as DFT can serve as a template for treating other complex physical/chemical processes as well. Published by AIP Publishing.
机译：使用程序升温解吸/反应方法研究了二氧化硅填充的聚二甲基硅氧烷（PDMS）复合材料M9787在真空/干燥环境中潜在的脱气现象。 463 K真空热处理的样品，随后再暴露于湿气的真空热处理的样品以及未经处理的样品的脱气动力学均采用等转化和约束迭代回归方法以互补的方式提取。还进行了与二氧化硅表面的水相互作用的密度泛函理论（DFT）计算，以提供对导致获得的动力学参数的结构图案的了解。动力学分析/模型表明，在随后的真空/干燥环境应用中，室温（类似于300 K）下，真空热处理过的样品未发生脱气现象。将真空热处理过的样品再次暴露在手套箱条件下（相当于H2O的体积比为30 ppm）几天的主要影响是在二氧化硅表面填料上形成了类似于60 ppm的物质。按重量计的物理吸附和松散结合的水分，随后在室温下于真空/干燥环境中经过10年的时间脱气。但是，如果不进行任何真空热处理，甚至在抽真空1小时后，在接下来的几个小时内，PDMS就会释放出约300 ppm重量的H2O。此后，除气速率大大降低。提出的使用等转化动力学分析结果和反应的适当性质作为约束条件的方法，可以更精确地进行复杂动力学谱的迭代回归分析/反卷积，并使用第一原理计算（例如DFT）检查如此获得的结果作为处理其他复杂物理/化学过程的模板。由AIP Publishing发布。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号