Controlled polymerization route to novel α-methyl styrene – olefin triblock copolymers with tailored architecture

In this study, well-defined α-methyl styrene – olefin triblock copolymers were synthesized via living anionic polymerization using alkyl lithium as an initiator and 1,12-dibromododecane as a coupling agent. The polymerization was conducted in cyclohexane under an inert atmosphere at moderate temperature, allowing for precise control over the molecular architecture and narrow molecular weight distribution. Gel permeation chromatography (GPC) revealed monomodal elution curves with dispersity values close to unity, confirming the living nature of the polymerization process and the high structural homogeneity of the resulting copolymers. Structural characterization was performed using 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The 1H NMR spectra confirmed the successful formation of block copolymers through the identification of characteristic chemical shifts corresponding to the initiator, αMS blocks, and central dodecane units. Notably, the absence of brominated end-groups in the spectrum supports complete coupling and high end-group fidelity. Furthermore, 13C NMR analysis revealed well-defined chemical shifts associated with aromatic, methine, and methylene carbons. The disappearance of signals corresponding to bromine-bound methylene carbons confirmed the full consumption of the coupling agent and the effective formation of the triblock structure. These findings validate the successful synthesis of αMS-based triblock copolymers with a high degree of control over molecular parameters, establishing a robust foundation for tailoring thermomechanical and morphological properties for advanced material applications.