Synergistic Photo- and Amine-Mediated Polymerization of Thioctic Acid Derivatives: Ultrafast Polymerization, Tunable Molar Mass, and Quantitative Monomer Recovery

Abstract

Poly(thioctic acid derivative)-based materials are attracting increasing attention, yet efficient polymerization strategies are few and unsatisfactory. Herein, this work reports a photoamine-mediated polymerization of thioctic acid derivatives, featuring multiple advantages. First, an ultrafast equilibrium is established for the polymerization of thioctic acid ethyl ester (TAEt) within 1 min, with a high conversion (>80%) when mediated by 1,3-propanediamine (1,3-PDA) in the presence of 405 nm light at room temperature. Second, the molar mass of the obtained polymers can be precisely programmed simply by varying the follow-up irradiation time after polymerization. Third, quantitative closed-loop recycling of the resulting polymers to the monomer at different stages is rapidly achieved within minutes by adding an excess of 1,3-PDA. Additionally, mechanistic investigation proves that this reaction occurs in the manner of anionic polymerization. Therefore, this work provides a facile and highly efficient strategy for the rapid and controllable synthesis and sustainable recycling of poly(thioctic acid derivative)-based materials.