Grudzien Rafal M, Blitz Jonathan P, Pikus Stanislaw, Jaroniec Mietek
Department of Chemistry, Kent State University, Kent, OH 44240, USA.
J Colloid Interface Sci. 2009 May 1;333(1):354-62. doi: 10.1016/j.jcis.2009.01.029. Epub 2009 Jan 17.
Ordered large-pore organosilicas with isocyanurate bridging groups were synthesized via co-condensation of tetraethyl orthosilicate (TEOS) and tris[3-(trimethoxysilyl)propyl]isocyanurate (ICS) in the presence of poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide) (EO(39)BO(47)EO(39)) B50-6600 template under acidic conditions. It was shown that the extraction of the B60-5500 triblock copolymer with acidified ethanol solution was insufficient to remove completely the template; however, calcination of as-synthesized and extracted samples under air atmosphere at 200 degrees C, 250 degrees C and 300 degrees C caused not only the removal of the polymer but also a substantial decomposition of the ICS groups. In contrast, the heat treatment of extracted organosilicas at 360 degrees C in flowing nitrogen was able to fully remove the residual template without degradation of the ICS bridging groups. Characterization of the resulting materials by small angle X-ray scattering (SAXS) and X-ray powder diffraction (XRD) revealed that isocyanurate-containing organosilicas have a body-centered cubic symmetry (Im3m). Argon adsorption-desorption isotherms of these organosilicas revealed cage-like mesopores, high surface areas and large pore volumes. The diameters of spherical cages were found to be very uniform in the range of 12-14 nm. A complete removal of triblock copolymer was confirmed by high-resolution thermogravimetry (TG), Fourier transform infrared spectroscopy (FT-IR) and CHNS elemental analysis (EA). The latter showed that the isocyanurate rings are intact in the framework and their loading is up to 1 mmol g(-1). Moreover, these organosilicas were also synthesized using low acid concentration, double amount of polymer and sodium chloride; in this case the template was completely extracted and there was no need for additional heat treatment.
在酸性条件下，通过正硅酸乙酯（TEOS）和三[3-（三甲氧基硅基）丙基]异氰脲酸酯（ICS）在聚（环氧乙烷）-聚（环氧丁烷）-聚（环氧乙烷）（EO(39)BO(47)EO(39)）B50-6600模板存在下的共缩合反应，合成了具有异氰脲酸酯桥连基团的有序大孔有机硅。结果表明，用酸化乙醇溶液萃取B60-5500三嵌段共聚物不足以完全去除模板；然而，在空气气氛中于200℃、250℃和300℃对合成并萃取后的样品进行煅烧，不仅会去除聚合物，还会导致ICS基团大量分解。相比之下，在流动氮气中于360℃对萃取后的有机硅进行热处理能够完全去除残留模板，而不会使ICS桥连基团降解。通过小角X射线散射（SAXS）和X射线粉末衍射（XRD）对所得材料进行表征，结果表明含异氰脲酸酯的有机硅具有体心立方对称性（Im3m）。这些有机硅的氩气吸附-脱附等温线显示出笼状介孔、高比表面积和大孔体积。发现球形笼的直径在12-14nm范围内非常均匀。通过高分辨率热重分析（TG）、傅里叶变换红外光谱（FT-IR）和CHNS元素分析（EA）证实了三嵌段共聚物已被完全去除。后者表明异氰脲酸酯环在骨架中保持完整，其负载量高达1mmol g(-1)。此外，还使用低酸浓度、双倍聚合物量和氯化钠合成了这些有机硅；在这种情况下，模板被完全萃取，无需额外的热处理。
