Chemically modified silica is widely used as a reinforcing filler in elastomers. The modification is generally done in situ while preparing the rubber. However, in order to increase the efficiency and facilitate the mixing process, the silica can be pre-treated by a 2-step molecular layer deposition. The precursors for the modification are 3-mercaptopropyl-triethoxysilane (MPTES) and octanoyl chloride (OC) to react with MPTES and form a blocked silane. The precipitated silica nanofiller was successfully treated with MPTES and showed a self-limiting behavior: saturation occurred at 2.7%. Furthermore, DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) analysis confirmed the successful deposition of MPTES on the silica surface by showing the -SH peak that appeared after the reaction of MPTES and silica. In the second step, OC was introduced to form a thioester on the surface of the MPTES-treated silica, controlling the reactivity of the mercapto group from MPTES by blocking it to prevent a negative influence on the processing behavior of the rubber. Thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS) analytical results confirmed the deposition of the blocked mercapto silane on the silica. TGA results demonstrated the self-limiting behavior of OC, and DRIFTS and XPS proved the thioester formation. A thioester peak after the 2nd reaction step with OC appeared. At the same time, the disappearance of the -SH signal from the MPTES was observed, indicating the formation of the blocked mercapto silane structure. Transmission electron microscopy results showed that the treated silica has a well-distributed carbon and sulfur deposition after MPTES/OC treatment.

化学改性二氧化硅广泛用作弹性体中的增强填料。改性通常在制备橡胶时就地进行。然而，为了提高效率并促进混合过程，可以通过两步分子层沉积对二氧化硅进行预处理。改性的前体是 3-巯基丙基三乙氧基硅烷 (MPTES) 和辛酰氯 (OC) 与 MPTES 反应并形成封闭的硅烷。沉淀二氧化硅纳米填料成功地用 MPTES 处理并表现出自限行为：饱和发生在 2.7%。此外，DRIFTS（漫反射红外傅立叶变换光谱）分析通过显示 MPTES 与二氧化硅反应后出现的 -SH 峰，证实了 MPTES 成功沉积在二氧化硅表面上。在第二步中，引入 OC 以在 MPTES 处理的二氧化硅表面形成硫酯，通过阻断 MPTES 的巯基来控制其反应性，以防止对橡胶的加工行为产生负面影响。热重分析 (TGA)、傅立叶变换红外光谱和 X 射线光电子能谱 (XPS) 分析结果证实了封闭的巯基硅烷在二氧化硅上的沉积。TGA 结果证明了 OC 的自限行为，DRIFTS 和 XPS 证明了硫酯的形成。在与 OC 的第 2 步反应后出现硫酯峰。同时，观察到来自 MPTES 的 -SH 信号消失，表明形成了封闭的巯基硅烷结构。