Rheological and mechanical properties of particle filled elastomers

Rheological and mechanical properties and particle dispersion state of silicone resin filled with various silica particles were investigated before and after crosslinking. Uncrosslinked resin filled with smaller particles at higher content showed higher storage rnodulus G' and complex viscosity \ eta(*) \ at lower frequency region and a second plateau was observed. When the particle size is almost identical, particle with hydrophilic surface made G' and \ eta(*) \ slightly higher. Front those results, liquid matrix containing smaller particles at higher content has stronger three-dimensional structure. This structure seems to be stronger in the hydrophobic matrix filled in the hydrophilic particles. On the other hand, small hydrophobic particles increased the storage modulus E' of crosslinked resin at the rubbery region. These increases in Eat the rubbery region reflect the increases in the tensile modulus and strength of particle filled elastomers in the tensile test. These results suggested that the three-dimensional network structure formed with hydrophilic particles in hydrophobic matrix increased elastic character when the matrix is uncrosslinked. However, once matrix is crosslinked, adhesion between particles and matrix enhances the mechanical properties.