Enhancing the damping and mechanical properties of phenyl silicone rubber by introducing phenyl MQ silicone resins as molecular fillers

Silicone rubber features excellent thermal stability, outstanding low-temperature performance, and superb processability, however, the poor damping property and low mechanical strength limit its applications. In this work, we synthesized two types of phenyl MQ resins as molecular fillers and incorporated them into phenyl silicone rubber to prepare damping composites. The effects of both the phenyl MQ resin structures and contents on the damping properties and mechanical performances were investigated. The results showed that phenyl MQ resins exhibit multiscale damping effects with temperature rising, and phenyl MQ resins are distributed in silicone rubber with a "sea-island" structure, which strengthen the mechanical property. The composite exhibit optimal performance with incorporating 30phr diphenyl MQ resins: the damping factor at 150 °C increased from 0.1 to 0.18, the temperature range for tan δ > 0.3 expanded by 115.2 %, and maintained a tensile strength of 6.3 MPa. This study paves a new path to design and prepare silicone rubber composite that balance high damping performances with better mechanical strength.