Jiang Yu, Zhu Hui, Chen Jianxu, Liao Saihu
Key Laboratory of Molecule Synthesis and Function Discovery College of Chemistry, Fuzhou University, Fuzhou, 350108, China.
Beijing National Laboratory for Molecular Science, Beijing, 100190, China.
Macromol Rapid Commun. 2023 Feb;44(4):e2200702. doi: 10.1002/marc.202200702. Epub 2022 Nov 29.
Herein, the successful development of a metal-free, solution [2 + 2] photopolymerization of natural cinnamic acid-derived bisolefinic monomers is reported, which is enabled by a strategy based on direct triplet state access via energy transfer catalysis. 2,2'-Methoxythioxanthone has been identified as an effective organic photocatalyst for the [2 + 2] photopolymerization in solution, which can be excited by visible light and activate the biscinnamate monomers via triplet energy transfer. This method features its metal-free conditions, visible light utilization, solution polymerization, and abundant biomass-based feedstock, as well as processable polymer products, which is different from the rigid, insoluble products obtained from solid-state photopolymerization. This solution polymerization method also shows a good compatibility to monomer structures; cinnamic acid-derived bisolefinic monomers with different linkers, including diamine, natural diol, and bisphenol, can all readily undergo [2 + 2] photopolymerization, and be transformed into colorless, sustainable polymers.
在此，我们报道了一种基于通过能量转移催化直接进入三重态策略实现的、无金属的天然肉桂酸衍生双烯烃单体的溶液[2 + 2]光聚合的成功开发。2,2'-甲氧基噻吨酮已被确定为溶液中[2 + 2]光聚合的有效有机光催化剂，它可被可见光激发，并通过三重态能量转移激活双肉桂酸酯单体。该方法具有无金属条件、可见光利用、溶液聚合、丰富的生物质基原料以及可加工的聚合物产物等特点，这与固态光聚合得到的刚性、不溶性产物不同。这种溶液聚合方法对单体结构也显示出良好的兼容性；具有不同连接基（包括二胺、天然二醇和双酚）的肉桂酸衍生双烯烃单体都能很容易地进行[2 + 2]光聚合，并转化为无色、可持续的聚合物。
