Enhanced cycle loading stability of shock transmission units via adjusting boron content of polyborosiloxanes

Polyborosiloxanes (PBSs)-based shock transmission units (STUs) play a vital role in the seismic resistance of the bridge due to the large output damping force and simple structure without the use of a valve structure. However, Dow Corning 3179 (DC3179)-based STU had poor locking performance under cyclic loads and filling processability due to excessive viscosity, which was unfavorable for engineering applications. In order to achieve the locking of the PBS-based STUs with low complex viscosities of PBSs under cyclic loading, three PBSs with different boron content were synthesized via the reaction of hydroxyl-terminated polydimethylsiloxane (PDMS-OH) and boric acid (H3BO3). The results showed that the variation of the silicon-boron ratios would affect the complex viscosity, storage modulus, and loss modulus. The essence is that the formation of a non-bonding crosslink between boron atoms with vacancies and oxygen atoms with lone electron pairs in adjacent chains affects the movement of molecular chains. PBSs with low complex viscosity and high storage modulus were prepared by adjusting the silicon-boron ratios, which could enhance the cyclic loading stability of PBS-based STUs.