MOLECULAR-ORIENTATION OF SILANE AT THE SURFACE OF COLLOIDAL SILICA
MOLECULAR-ORIENTATION OF SILANE AT THE SURFACE OF COLLOIDAL SILICA
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DOI：
10.1177/00220345930720061001
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发表时间：
1993-06-01
影响因子：
7.6
通讯作者：
SHANG, SW
中科院分区：
文献类型：
--
作者：
SODERHOLM, KJM;SHANG, SW
本研究的目的是研究牙科复合材料填充界面上二氧化硅-硅烷键的形成。利用漫反射红外傅里叶变换光谱分析了不同浓度的甲基丙烯酰氧丙基三甲氧基硅烷(MPS)处理的热解二氧化硅(Cab-O-Sil)的光谱。研究结果表明，γ-甲基丙烯氧丙基三甲氧基硅烷(MPS)分子平行于胶体二氧化硅表面(Cab-O-Sil)，并形成两种类型的键。其中一个键是硅氧烷桥，它是由二氧化硅表面的硅醇基和硅烷的水解物之间的缩合反应形成的。水在反应过程中形成，并很快被二氧化硅表面的硅醇基团重新捕获。在实验条件下，这些水分子不能用于未水解硅烷的额外水解反应。由于该反应，孤立的OH-基团的强度降低。在缩合反应的同时，MPS分子中的羰基形成了氢键。这种氢键的形成导致了羰基带的峰从1718-1720 cm-1移动到1700-1702 cm-1。这种氢键的形成也发生在孤立的OH-基团上。在消耗了分离的OH-基团之后，没有发生额外的表面反应，因为没有更多的OH-基团可用于额外的缩合反应或形成氢键。结果表明，填料处理所需的硅烷量取决于填料表面可用的孤立OH-基团的数量。
The objective of this study was to investigate the silica-silane bond formation present at the filler interface of dental composites. Diffuse reflectance infrared Fourier transform spectroscopy was used, and the spectra of pyrogenic silica (Cab-O-Sil) treated with different concentrations of gamma-methacryloxypropyltrimethoxy-silane (MPS) were analyzed. The outcome of the study suggested that the gamma-methacryloxypropyltrimethoxysilane (MPS) molecules oriented parallel to the colloidal silica surface (Cab-O-Sil) and formed two types of bonds. One of these bonds was a siloxane bridge formed by a condensation reaction between the silanol groups of both the silica surface and the hydrolyzed silane. Water formed during this reaction and soon became recaptured by the silanol groups of the silica surface. These water molecules were not available for additional hydrolyzation reactions of the unhydrolyzed silane under the experimental conditions. The intensity of the isolated OH-groups decreased because of this reaction. Simultaneous with the condensation reaction, the carbonyl group of the MPS molecule formed hydrogen bonds. This hydrogen bond formation resulted in a peak shift of the carbonyl band from 1718-1720 cm-1 to 1700-1702 cm-1. This hydrogen bond formation also occurred with the isolated OH-groups. After consumption of the isolated OH-groups, no additional surface reaction occurred because no further OH-groups were available for additional condensation reactions or hydrogen bond formation. The findings suggest that the amount of silane needed for filler treatment depends on the number of isolated OH-groups available on the filler surface.