Abstract
An initiating system composed of GaCl3 and an alkylbenzene was demonstrated to be highly effective for the controlled cationic polymerization of a plant-derived monomer, β-pinene. Alkylbenzenes such as pentamethylbenzene and hexamethylbenzene were shown to function as suitable additives for the polymerization of β-pinene, an alkene monomer with low reactivity, although the alkylbenzenes are much less basic than conventional additives such as esters and ethers for base-assisting living cationic polymerization. For example, when two equivalents of hexamethylbenzene were added to GaCl3 in conjunction with 2-chloro-2,4,4-trimethylpentane as an initiator, cationic polymerization of β-pinene successfully proceeded in a living manner at –78 °C. Successful control over the reaction, i.e., control of an active–dormant equilibrium, was attributed to the formation of a complex between GaCl3 and the alkylbenzene, as confirmed by UV–vis and 71Ga NMR analyses.
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Acknowledgements
This work was partially supported by a Grant-in-Aid for Scientific Research (No. 22107006) on Innovative Areas of ‘Fusion Materials’ (No. 2206) from MEXT.
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Karasawa, Y., Kimura, M., Kanazawa, A. et al. New initiating systems for cationic polymerization of plant-derived monomers: GaCl3/alkylbenzene-induced controlled cationic polymerization of β-pinene. Polym J 47, 152–157 (2015). https://doi.org/10.1038/pj.2014.108
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DOI: https://doi.org/10.1038/pj.2014.108
