Living ROMP of N-phenothiazinyl norbornene-dicarboximide homopolymer: Synthesis, characterization, and physical behavior insights

A novel phenothiazine-norbornene dicarboximide (PT-NDI) monomer was synthesized via a one-pot catalytic esterification reaction. The structural characterization of the monomer was conducted using EI-MS, FT-IR, and spectroscopic 1D and 2D-NMR techniques. Poly (PT-NDI) homopolymers were subsequently prepared through ROMP employing different Grubbs initiators. The polymerization kinetics were monitored using NMR and GPC analyses, with complete monomer conversion observed after 48 min. Furthermore, living homo-polymerization was assessed at various [Monomer/Initiator] ratios, corresponding to different repeating units (n). The efficiency of various Grubbs catalysts in the homopolymerization process was also evaluated, with results indicating that the Grubbs 1st generation catalyst provides more efficient control over molecular weights and narrow polydispersity (PDI). The UV–visible absorption maximum was observed at approximately 309 nm, with the band gap values spanning 3.47–3.51eV. Thermal stability was evaluated through TGA and DSC, revealing decomposition temperatures within the range of 395 °C to 398 °C, and glass transition temperatures (T_g) ranging from 171.2 °C to 175.3 °C. The synthesized homopolymers exhibited remarkable thermal stability and high T_g values, indicating their potential applicability in various engineering domains.