Abstract
Rheological and mechanical properties of silicone resins filled with various silica particles were investigated before and after crosslinking. Both hydrophilic and hydrophobic particles were prepared from tetraethoxysilane and vinyltriethoxysilane, respectively in a liquid silicone matrix through a sol-gel process. Vinyl groups on the surface of the hydrophobic particles react with silicone resin. Rheological investigation for the uncrosslinked resin filled with particles revealed that the liquid polymer matrix containing hydrophilic particles has a strong three-dimensional structure. While the hydrophilic particle tends to form a three-dimensional structure, the hydrophobic particle in the liquid silicone matrix suppressed such tendency. Once matrix is crosslinked, although the three-dimensional structure of the hydrophilic particles gives rise to the slight increase in tensile modulus, the tensile strength and the elongation at break decrease. However, adhesion between hydrophobic particles and the matrix enhances the mechanical properties significantly.
