Controlled synthesis of tertiary amine functionalized 1,3-pentadiene-based copolymers via living anionic copolymerization with 4-vinylbenzylpiperidine

VBMP serves as both a weakly coordinating polarity regulator and a pendant functional group, achieving “one reagent, two functions” and enabling quantitative functionalization with controlled microstructure. • The significantly higher reactivity of VBMP ( r VBMP  = 2.79–3.10) over PD ( r PD  = 0.02–0.11) provides a thermodynamic basis for constructing composition-gradient sequences in functionalized polydienes. • A synergistic N–Li coordination involving both chain-end active centers and in-chain tertiary amine groups explains how low mole fractions of VBMP dramatically affect chain segment regularity in non-polar solvents. To develop 1,3-diene-based polymers with both tertiary amine functionalization and controllable microstructure, in this work, 4-vinylbenzylpiperidine (VBMP) was used as a tertiary amine functional monomer and achieves the controlled copolymerization of VBMP and 1,3-Pentadiene (PD) under mild conditions above room temperature in cyclohexane solvent by using living anionic polymerization. By taking advantage of the dual functions of VBMP as both a comonomer and a polarity regulator, and through optimizing the monomer feed ratio, poly(PD- co -VBMP) copolymers with controllable molecular weight and narrow molecular weight distribution (1.08 <  Đ  < 1.15) were successfully prepared. 1 H NMR spectroscopy and Fourier Infrared analysis confirmed that VBMP was inserted into the polymer backbone through in situ copolymerization, with a controlled functionalization degree. The detailed instantaneous composition distribution under different feed ratios was obtained through online 1 H NMR analysis. The reactivity ratios ( r PD  = 0.02–0.11 and r VBMP  = 2.79–3.10) were obtained by Fineman-Ross and Kelen-Tudos methods. Moreover, DSC analysis indicated that as the content of VBMP increased, the glass transition temperature ( T g ) of the copolymers gradually rose from −10 °C to 49 °C, and the regularity of the chain segments was significantly improved. In addition, the LAP (living anionic polymerization) chain end active center coordination mechanism, and the N-Li coordination synergy mechanism in the polymer backbone were proposed to explain the experimental results. In summary, this polymerization system not only exploits the weak regulatory effect of the tertiary amine group of VBMP on anionic polymerization but also achieves tertiary amine functionalization of 1,3-pentadiene-based gradient sequence copolymers, providing an efficient approach for preparing functional materials with both elastic properties and reactive sites. Download: Download high-res image (144KB) Download: Download full-size image