Spectroscopic characterisation of hydroxyapatite and nanocrystalline apatite with grafted aminopropyltriethoxysilane: nature of silane-surface interaction
Spectroscopic characterisation of hydroxyapatite and nanocrystalline apatite with grafted aminopropyltriethoxysilane: nature of silane-surface interaction
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DOI：
10.1007/s10853-015-9122-x
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发表时间：
2015-09-01
影响因子：
4.5
通讯作者：
Rey, Christian
中科院分区：
文献类型：
--
作者：
Michelot, Audric;Sarda, Stephanie;Rey, Christian
多相均相催化通常用通过吸附或通过共价分子键接枝在固体上的分子催化剂进行。有机基团在固体载体上的共价接枝通常使用官能化的三烷氧基硅烷通过甲硅烷基化进行。在这些固体载体中，很少有关于磷灰石的研究。在本工作中，氨丙基三乙氧基硅烷（APTES）接枝在甲苯中进行不同的磷灰石支持：结晶化学计量羟基磷灰石不同的干燥方法，冷冻干燥（HAP）和干燥在100 A度C（HAPD），和纳米晶磷灰石。在接枝之前和之后，对所有材料进行充分表征，以更好地理解烷氧基硅烷/表面相互作用的性质。数据表明，APTES的共价接枝和其缩聚反应之间存在明显的竞争，这取决于固体载体表面的性质。甲硅烷基化伴随着APTES共价接枝到磷灰石结构的羟基和/或存在于表面水合层上的OH-物质的氧原子。本工作阐明了硅烷接枝到选定的磷灰石表面上的性质，特别是磷灰石表面的组成和性质对硅烷化过程的影响。
Heterogenised homogeneous catalysis is commonly performed with molecular catalysts grafted on solids via adsorption or via a covalent molecular link. Covalent grafting of organic groups on solid supports is usually carried out by silylation, using functionalised trialkoxysilanes. Among these solids supports, very few studies have been published on apatites. In the present work, aminopropyltriethoxysilane (APTES) grafting was performed in toluene on different apatitic supports: crystallised stoichiometric hydroxyapatites differing by the drying method, freeze-dried (HAP) and dried at 100 A degrees C (HAPD), and a nanocrystalline apatite. All materials were fully characterised, before and after grafting, for better understanding of the nature of the alkoxysilane/surface interaction. The data show a clear competition between the covalent grafting of APTES and its polycondensation reaction, depending on the nature of the solid support surface. Silylation is accompanied by APTES covalent grafting to oxygen atom of the hydroxyl groups of the apatitic structure and/or of the OH- species that are present on the surface hydrated layer. This work clarifies the nature of silane grafting onto selected apatitic surfaces and especially the influence of the composition and properties of the apatitic surfaces on the process of silylation.