Direct Synthesis of Functional Thermoplastic Elastomer with Excellent Mechanical Properties by Scandium‐Catalyzed Copolymerization of Ethylene and Fluorostyrenes

Abstract

AbstractHerein, we report copolymerizations of ethylene (E) and ortho‐/meta‐/para‐fluorostyrenes (SF=oFS/mFS/pFS) by using quinolyl methylene fluorenyl scandium complex (Flu‐CH2‐Qu)Sc(CH2SiMe3)2. The copolymerizations proceed in a controlled fashion to afford copolymers composed of “soft” ethylene‐fluorostyurene (E–SF) random segments (Tg=−22.2–5.1 °C) and “hard” crystalline ethylene–ethylene (E–E) segments (Tm=42.3–130.2 °C). The copolymers behave like thermoplastic elastomers at room temperature by showing high stress values up to 39.5 MPa under elongation‐at‐break above 774 % with elastic recovery over 75 %. The excellent mechanical properties are mainly attributed to the microphase separation of the nanoscale crystalline E–E domain from the amorphous E–SF copolymer matrix proved by AFM, WAXD and SAXS. The mechanism investigation by the density functional theory (DFT) simulation reveals that the steric bulky and electron‐withdrawing ligand of the catalytic precursor prefers E propagation to generate long E–E segments, while the incorporation of SF is thermodynamic control.