三乙氧基硅烷
环氧树脂
材料科学
纳米复合材料
联轴节(管道)
复合材料
溶剂
化学工程
高分子化学
有机化学
化学
工程类
作者
F. Branda,Dambarudhar Parida,Robin Pauer,Massimo Durante,Sabyasachi Gaan,Giulio Malucelli,Aurelio Bifulco
出处
期刊:Polymers
[MDPI AG]
日期:2022-09-15
卷期号:14 (18): 3853-3853
被引量:8
标识
DOI:10.3390/polym14183853
摘要
Uniformly distributed silica/epoxy nanocomposites (2 and 6 wt.% silica content) were obtained through a "solvent-free one-pot" process. The inorganic phases were obtained through "in situ" sol-gel chemistry from two precursors, tetraethyl orthosilicate (TEOS) and (3-aminopropyl)-triethoxysilane (APTES). APTES acts as a coupling agent. Surprisingly when changing TEOS/APTES molar ratio (from 2.32 to 1.25), two opposite trends of glass transformation temperature (Tg) were observed for silica loading, i.e., at lower content, a decreased Tg (for 2 wt.% silica) and at higher content an increased Tg (for 6 wt.% silica) was observed. High-Resolution Transmission Electron Microscopy (HRTEM) showed the formation of multi-sheet silica-based nanoparticles with decreasing size at a lower TEOS/APTES molar ratio. Based on a recently proposed mechanism, the experimental results can be explained by the formation of a co-continuous hybrid network due to reorganization of the epoxy matrix around two different "in situ" sol-gel derived silicatic phases, i.e., micelles formed mainly by APTES and multi-sheet silica nanoparticles. Moreover, the concentration of APTES affected the size distribution of the multi-sheet silica-based nanoparticles, leading to the formation of structures that became smaller at a higher content. Flammability and forced-combustion tests proved that the nanocomposites exhibited excellent fire retardancy.
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