Nonlinear rheology of silicone rubber composites with tailored mechanical and dielectric properties

Silicone rubber (SR) composites used in electronics demand tailored mechanical and dielectric properties. Herein cellulose nanocrystal and graphene are used as promising nanofillers for SR vulcanizates and a simple method of alignment of the fillers is explored to mediate the mechanical, dielectric and nonlinear rheological responses. The results reveal that the alignment of fillers tends to improve deformational stress and lower dielectric constant and loss, allowing preparing high-performance composites with dielectric constant being comparable with the electroinsulating SR vulcanizates. Under dynamic oscillating shear deformation, the composites demonstrate both elastic and viscous nonlinearities while the filler alignment improves the elastic and lowers the dissipation without marked influence of the relative amplitude of the Payne effect. The investigation provides a perspective for manufacturing SR composites with high elasticity and low mechanical and dielectric losses.