Interphase-layer effect on deformation of silicone rubber filled with nanosilica particles

The viscoelastic and statically tensile deformation properties of silicone rubber composites filled with nanosilica (300 nm in diameter) and microsilica particles (1.5 mu m in diameter) were investigated on the basis of experimental results to clarify the interphase-layer effect on these properties. The interphase layers formed around the nanoparticles without chemical coating were found to be glassy, even though the composites were in the rubbery state. The interphase layer thickness was determined to be approximately 20 nm using Guth and Gold's mixture law with the viscoelastic properties of the nanoparticle-filled rubber in the rubbery state. The determined thickness of the interphase layer was confirmed by comparing the maximum strains at fracture for the nanoparticle-filled rubber, which decreased for higher volume fraction of the nanoparticles. Therefore, the deformation properties were clarified to depend on the volume fraction of the apparent particles composed of the nanoparticles and interphase layers. (C) 2017 Wiley Periodicals, Inc.