Torres Xavier M, Stockdale John R, Pacheco Adam, Legett Shelbie A, Bezek Lindsey B, Benedikt Bart, Labouriau Andrea, Adhikari Santosh
C-CDE: Chemical Diagnostics and Engineering Group, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
W-13: Advanced Engineering Analysis, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Polymers (Basel). 2025 Jul 21;17(14):1998. doi: 10.3390/polym17141998.
Room-temperature vulcanizing (RTV) silicone foams are used in many industrial applications that require the material to perform over long time periods. However, mechanical properties tend to deteriorate when these foams age under a compressive load. The chemical aging is attributed to the presence of unreacted functional groups of the prepolymers, residues from acid, and catalytically active tin (II) species. Here, an optimized thermal treatment of an RTV foam that achieves completion of curing reactions and deactivation of reactive species is proposed. Foams that were thermally aged for three months under compressive load showed no signs of compression set, indicative of the effectiveness of the implemented post-curing approach. In addition, the effects of fillers (diatomaceous earth, fumed silica, and carbon nanofibers) on thermomechanical properties were investigated. Tensile strength, tear strength, and thermal conductivity increased when these fillers were added to the unfilled RTV formulation, with carbon nanofibers (CNFs) being the most effective filler. Rheological studies of RTV formulations indicated that 2.5 wt.% of CNFs is the upper limit that can be added to the RTV formulation.
室温硫化（RTV）硅泡沫用于许多需要材料长期发挥作用的工业应用中。然而，当这些泡沫在压缩载荷下老化时，其机械性能往往会恶化。化学老化归因于预聚物中未反应的官能团、酸的残留物以及具有催化活性的锡（II）物种的存在。在此，提出了一种对RTV泡沫进行优化热处理的方法，该方法可使固化反应完全完成并使活性物种失活。在压缩载荷下热老化三个月的泡沫没有出现压缩永久变形的迹象，这表明所实施的后固化方法是有效的。此外，还研究了填料（硅藻土、气相二氧化硅和碳纳米纤维）对热机械性能的影响。当将这些填料添加到未填充的RTV配方中时，拉伸强度、撕裂强度和热导率均有所提高，其中碳纳米纤维（CNF）是最有效的填料。RTV配方的流变学研究表明，2.5 wt.%的CNF是可以添加到RTV配方中的上限。
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