Application of Simple Cycloalkylsilanetriols as Surface Modifier for Inorganic Particles
- PDF / 184,761 Bytes
- 6 Pages / 595 x 842 pts (A4) Page_size
- 59 Downloads / 174 Views
1174-V06-08
Application of Simple Cycloalkylsilanetriols as Surface Modifier for Inorganic Particles Bok Ryul Yoo, Dong Euy Jung, and Joon Soo Han Organosilicon Chemistry Lab. Korea Institute of Science & Technology
ABSTRACT Simple cycloalkylsilanetriols RSi(OH)3 [R =c- pentyl (1) and c-hexenyl (2)] were synthesized as white powders in 70 and 90% isolated yields, respectively, from the hydrolysis of the corresponding trialkoxysilanes with mild acidic water. Silanetriols 1,2 are soluble in water and polar organic solvents such as alcohol, acetone, THF, DMSO, and etc. They can be applied as surface modifiers for inorganic materials such as silica and titania through simple two step processes: 1) organosilanetriol interact with hydroxyl groups on inorganic materials through hydrogen bonding to make molecular layered thin coating on the inorganic surface, 2) then can undergo condensation by heating about 110 ℃ above to form M-O-Si covalent bond to give hydrophobic silica. With the treatment of ca. 50 nm spherical silica with 5 wt % alkylsilaneol 1, no precipitation of silica particles in water was observed, indicating good surface modifiers for silica particle. In this presentation we will discuss the application of silanetriols as surface modifier for inorganic materials such as silica and titania particles. INTRODUCTION Inorganic oxide particles such as silica and titania are utilized as fillers for inorganicorganic polymer composites to obtain excellent fill-ability, thermal conductivity, viscosity characteristics, good mechanical, and electric properties.1 There are hydrophilic characters due to hydroxyl groups on surfaces of inorganic particles. This hydrophilic surface does not process good compatibility with organic polymer, and therefore the silica cannot be dispersed very well into the polymers. While the inorganic particles with hydrophilic surface easily adhere to each other through hydrogen bonding network leading to irregular agglomerations.2 The agglomerations of the inorganic particles can form a network through the whole polymer matrix and occlude liquid polymer in their inter-particle voids, thereby affecting the rheology of the composite and giving a significant rise to the viscosity as inorganic filler loading increases.3 Thus the surface modification of inorganic particles can be changed to be hydrophobic property from hydrophilic. Generally silylation of inorganic particles using organosilane coupling agents such as organoalkoxysilane and organochlorosilane is the most commonly used method for surface modification.4,5 The organic groups were attached to the surface of inorganic particle via the non-hydrolysable Si-C covalent bond and functioned as hydrophobic or/and network binder. It has also been known that the stability of particulate SiO2 or TiO2 dispersed in non-polar organic media is significantly improved when the surface of the particles is modified with organosilane coupling agents. There are many factors affecting the result of inorganic particle surface treatment, including the type of
Data Loading...
