Olefin polymerization and copolymerization
Fakhrossadat Mirtaleb; Mohammadreza Jozaghkar; Farshid Ziaee
Abstract
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 ...
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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.
Olefin polymerization and copolymerization
Mohammad Reza Jozaghkar; Farshid Ziaee
Abstract
Innovative strides in polymer synthesis have led to the successful living anionic polymerization of styrene-olefin triblock copolymers, yielding varying molecular weights and a remarkably narrow dispersity (Đ) in cyclohexane solvent at 45°C, initiated by n-butyllithium. The novel approach employs ...
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Innovative strides in polymer synthesis have led to the successful living anionic polymerization of styrene-olefin triblock copolymers, yielding varying molecular weights and a remarkably narrow dispersity (Đ) in cyclohexane solvent at 45°C, initiated by n-butyllithium. The novel approach employs anionic polymerization, augmented by the aid of a coupling agent known as 1,12-dibromododecane. Unlike traditional alcohol-based methods employed in polystyrene synthesis, this coupling agent, introduced at the end of the reaction, grafts two living macro-styrene chains with the dodecane chain, effectively acting as the pivotal second component in the formation of the triblock copolymer. Extensive experimentation pinpointed 45°C as the optimal temperature for anionic copolymerization in cyclohexane solvent. The comprehensive analysis, encompassing 13C NMR, 1H NMR, FTIR spectroscopy, and GPC, confirms the successful synthesis of styrene-dodecane-styrene triblock copolymer. The NMR results illustrate successful molecular structures, while GPC attests to the precision, showing a narrow Đ of below 1.2. This pioneering approach not only underscores the efficiency of anionic polymerization in the synthesis of styrene-olefin-styrene triblock copolymer using termination strategy but also promises extensive implications in material science and industrial applications.
