POS1-0381
Development of Photocontrolled Nitroxide-Mediated Polymerization by Photothermal Conversion
When and Where
Nov 30, -0001
12:00am - 12:00am
Presenter(s)
Seima Kondo (Graduate School of Engineering, Nagoya University)
Co-Author(s)
Abstract
Photothermal catalysis, which converts light energy into heat, has attracted increasing attention as a strategy for promoting thermal reactions under light irradiation. Photothermal catalysts, such as carbon black (CB), have been applied to various chemical reactions, including the depolymerization of polystyrene. Nitroxide-mediated polymerization (NMP) is a representative controlled/living radical polymerization method, in which the C–ON bond of alkoxyamines serves as a dormant species and is reversibly activated by heat to generate growing radical species. However, NMP generally requires high temperatures, and photocontrol of this process remains limited. We envisioned that photothermal catalysts could enable the activation of alkoxyamines under light irradiation.
In this study, photothermally controlled NMP of vinyl monomers was investigated using various photothermal catalysts (PTCs) under light irradiation. Radical polymerization of styrene (St) was conducted using St–TEMPO, an adduct of styrene and TEMPO, as an alkoxyamine initiator in conjunction with carbon black (CB) as a photothermal catalyst under blue LED irradiation. In the dark, the polymerization hardly proceeded. In contrast, under blue LED irradiation, the monomer conversion reached 75% after 74 h. The number-average molecular weights (Mn) of the products agreed well with theoretical values assuming that one molecule of alkoxyamine generates one polymer chain, and the polymers exhibited narrow dispersities (Đ = 1.15). These results indicate that photothermally controlled NMP of St was achieved using CB as a photothermal catalyst.
Additionally, various PTCs, including carbon nanotubes and magnetite, as well as different alkoxyamines, were employed to investigate the effects of their structures on the polymerization. The applicability of this method to various monomers, including methacrylates, which are typically difficult to control in conventional NMP systems, was also investigated.
In this study, photothermally controlled NMP of vinyl monomers was investigated using various photothermal catalysts (PTCs) under light irradiation. Radical polymerization of styrene (St) was conducted using St–TEMPO, an adduct of styrene and TEMPO, as an alkoxyamine initiator in conjunction with carbon black (CB) as a photothermal catalyst under blue LED irradiation. In the dark, the polymerization hardly proceeded. In contrast, under blue LED irradiation, the monomer conversion reached 75% after 74 h. The number-average molecular weights (Mn) of the products agreed well with theoretical values assuming that one molecule of alkoxyamine generates one polymer chain, and the polymers exhibited narrow dispersities (Đ = 1.15). These results indicate that photothermally controlled NMP of St was achieved using CB as a photothermal catalyst.
Additionally, various PTCs, including carbon nanotubes and magnetite, as well as different alkoxyamines, were employed to investigate the effects of their structures on the polymerization. The applicability of this method to various monomers, including methacrylates, which are typically difficult to control in conventional NMP systems, was also investigated.
