Study on the high‐temperature damping properties of silicone rubber modified by boron‐terminated polysiloxane

• Published in: Journal of applied polymer science 2023-01, Vol.140 (1), p.n/a
• Main Authors: Cui, Hongwei, Jing, Qian, Li, Dongwei, Zhuang, Tingting, Gao, Yixing, Ran, Xianghai
• Format: Article
• Language: English
• Subjects: Boron; Damping; damping properties; dative bonds; Dynamic mechanical analysis; Energy dissipation; Fourier transforms; High temperature; Liquid chromatography; Materials science; Molecular structure; NMR; Nuclear magnetic resonance; PBS; Polydimethylsiloxane; Polymers; Polysiloxanes; Rheological properties; Rheology; Rubber; Silicone rubber; Silicones
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.53262

Rubber damping materials have important applications in modern industrial systems. However, their damping temperature range is low, which is not suitable for the damping demand under high temperature conditions. At present, there is very little research on the damping performance of rubber under high temperature conditions. Silicone rubber has excellent high temperature resistance but poor damping in its application temperature range. In this study, a boron‐terminated polysiloxane (PBS) was prepared by modifying hydroxy‐terminated polydimethylsiloxane (PDMS‐OH) with boric acid (BA). The molecular structure of PBS was confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) analysis. Rheology measurements revealed that PBS was a “shear hardening” material. Then, the silicone rubber was modified with PBS. With the introduction of boron atoms, boron and oxygen dative bonds with dynamic properties could be formed inside the silicone rubber, which played an energy dissipation role in the process of association/dissociation. Dynamic mechanical analysis (DMA) showed that the loss factor (tan δ) of modified silicone rubber was greater than 0.3 in the temperature range of 81.5°C–250°C, which was higher than the loss temperature range of conventional damping rubber. The cyclic stress–strain test also showed that the modified silicone rubber still had high dissipation coefficient (DE) at high temperature. Therefore, the PBS‐modified silicone rubber prepared by this method achieved excellent damping performance under high temperature conditions. The boron atoms in boron‐terminated polysiloxane (PBS) formed dynamic dative bonds with the oxygen atoms in silicone rubbers. The dative bonds repeatedly broken or reconnected and dissipation of energy during the dynamic stretching.