Reprocessable Fluoro-Glycidyl Acrylate-Butadiene Rubbers via In Situ Cross-Linker Chain Extension and Hydrophobic Silica: Achieving Enhanced Tensile Strength and Surface Fluorine Enrichment

Fluorinated (meth)acrylate polymers have gained significant attention in marine antifouling, aerospace, and microelectronics applications owing to their exceptional surface properties. Current research focuses on two distinct approaches: mechanical reinforcement through cross-linking and fillers and surface hydrophobicity improvement via surface fluorine enrichment. However, these strategies present inherent limitations─the former compromises hydrophobicity by restricting fluorinated side chain migration, while the latter often sacrifices mechanical integrity. To address this challenge, we developed a reprocessable fluoro-glycidyl acrylate-butadiene rubber (FGBR) incorporating in situ cross-linker chain extension and hydrophobic silica filler. The introduction of a chain extender (20 wt %) enabled in situ formation of extended cross-linked networks, yielding remarkable 114% and 162% enhancements in tensile strength and toughness, respectively. Concurrently, hydrophobic silica (40 phr) effectively reduced interchain polarity, promoting fluorinated side chain migration to the surface. This synergistic approach achieved concurrent optimization of mechanical properties (18.6 MPa tensile strength) and surface hydrophobicity (132.2° water contact angle). Notably, the dynamic β-hydroxy ester and disulfide bonds within the cross-linked network endowed the material with excellent thermal reprocessability. This design, combining in situ chain extension with silica nanocomposites, represents a significant advancement in fluorinated methacrylate elastomers.