High-strength fluorosilicone rubber with exceptional shape memory performance obtained through stereochemical structure regulation

Abstract

The unique chain structure of fluorinated polysiloxane endows fluorosilicone rubber (FSR) with exceptional resistance to non-polar media, making it a widely employed sealing material in aerospace engines, vehicles, ships, and various industries. However, FSR with inherent structural limitations still suffers from low tensile strength. In this study, a high isotacticity of 37.35% in FSR was achieved through precise stereochemical structure regulation, thereby successfully incorporating strain-induced crystallization (SIC) into FSR. The stereo sequence distribution was confirmed through quantitative analysis using ¹⁹F NMR, while the SIC effect was verified via in situ synchrotron radiation WAXS. The SIC effect arising from high stereochemical structural regularity leads to FSR exhibiting exceptional tensile strength, with a remarkable increase of 38% compared to that of traditional random FSR, achieving an impressive value of 14.5 MPa. Meanwhile, the impacts of isotacticity, molecular weight, and temperature response on the mechanical properties of FSR were systematically investigated. Moreover, the stereoregular FSR exhibits exceptional shape memory performance with the shape fixation rate and shape recovery rate approaching 100%, whereas traditional FSR lacks such capability. This study not only overcomes the longstanding challenge of low tensile strength in FSR but also highlights the significant potential of utilizing stereoregular FSR in intelligent sensing applications.