Castellano Maila, Conzatti Lucia, Turturro Antonio, Costa Giovanna, Busca Guido
Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso 31, 16146 Genova, Italy.
J Phys Chem B. 2007 May 3;111(17):4495-502. doi: 10.1021/jp0702144. Epub 2007 Apr 10.
A good dispersion of silica into elastomers, typically used in tire tread production, is obtained by grafting of the silica with multifunctional organosilanes. In this study, the influence of the chemical structure of a triethoxysilane (TES), octadecyltriethoxysilane (ODTES), and ODTES/bistriethoxysilylpropyltetrasulfane (TESPT) mixture was investigated by inverse gas chromatography (IGC) at infinite dilution. Thermodynamic results indicate a higher polarity of the silica surface modified with TES as compared to that of the unmodified silica due to new OH groups deriving from the hydrolysis of ethoxy groups of the silane; the long hydrocarbon substituent of the ODTES lies on the surface of silica and reduces the dispersive component of the silica surface tension. A comparison with silica modified with TESPT is discussed. An accurate morphological investigation by transmission electron microscopy (TEM) and automated image analysis (AIA) was carried out on aggregates of silica dispersed into a SBR compound loaded with 35 phr (per hundred rubber) of untreated and TESPT-treated silica. Morphological descriptors such as the projected area/perimeter ratio (A/P) and roundness (P2/4piA) provided direct and quantitative indications about the distribution of the filler into the rubber matrix.
通过用多功能有机硅烷接枝二氧化硅，可在通常用于轮胎胎面生产的弹性体中实现二氧化硅的良好分散。在本研究中，通过无限稀释反相气相色谱法（IGC）研究了三乙氧基硅烷（TES）、十八烷基三乙氧基硅烷（ODTES）以及ODTES/双三乙氧基硅丙基四硫化物（TESPT）混合物的化学结构的影响。热力学结果表明，由于硅烷乙氧基水解产生新的羟基，与未改性的二氧化硅相比，用TES改性的二氧化硅表面具有更高的极性；ODTES的长烃取代基位于二氧化硅表面，降低了二氧化硅表面张力的色散成分。文中讨论了与用TESPT改性的二氧化硅的比较。通过透射电子显微镜（TEM）和自动图像分析（AIA）对分散在含有35份（每百份橡胶）未处理和TESPT处理的二氧化硅的丁苯橡胶复合材料中的二氧化硅聚集体进行了精确的形态学研究。形态学描述符，如投影面积/周长比（A/P）和圆度（P²/4πA），提供了关于填料在橡胶基体中分布的直接和定量指示。
