Jäger Katharina S C, Ammini Gayathri Dev, Voorter Pieter-Jan, Subramanian Priya, Kumar Anil, Anastasaki Athina, Junkers Tanja
Polymer Reaction Design Group, School of Chemistry, Monash University, 19 Rainforest Walk, Building 23, Clayton, VIC 3800, Australia.
Laboratory of Polymeric Materials, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, Zurich 8093, Switzerland.
J Am Chem Soc. 2025 Jan 8;147(1):594-602. doi: 10.1021/jacs.4c12455. Epub 2024 Dec 19.
A continuous flow setup comprising an inline dialysis unit for immediate monomer removal is used for the depolymerization of poly(methyl methacrylate) (pMMA), synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The approach used allows one to carry out solution depolymerizations at much higher polymer content compared to batch processes while maintaining high depolymerization conversions. pMMA is efficiently depolymerized in the flow reactor, yielding up to 68% monomer recovery under catalyst-free reaction conditions at 160 °C, starting from a 1 molar repeat unit concentration, which is a 20-fold improvement compared to previous batch studies. This was achieved by using the inline dialysis to continuously remove monomer from the depolymerization solution and hence continuously shifting of the depolymerization equilibrium to the recycling side. Depolymerizations at various temperatures, starting polymer concentrations, and reactor setup modifications are investigated, clearly showing the highly advantageous effect of the monomer removal on the reaction. The employed approach represents a significant advancement toward the industrial feasibility of depolymerization of methacrylates by lowering the solvent use, expanding its temperature operation window, and bringing polymer contents to a practically relevant level.
一种连续流动装置，包括用于立即去除单体的在线透析单元，用于通过可逆加成-断裂链转移（RAFT）聚合合成的聚（甲基丙烯酸甲酯）（pMMA）的解聚。与间歇法相比，所采用的方法允许在更高的聚合物含量下进行溶液解聚，同时保持高解聚转化率。pMMA在流动反应器中有效地解聚，在160℃无催化剂反应条件下，从1摩尔重复单元浓度开始，单体回收率高达68%，与之前的间歇研究相比提高了20倍。这是通过使用在线透析从解聚溶液中连续去除单体，从而使解聚平衡持续向再循环方向移动来实现的。研究了在不同温度、起始聚合物浓度和反应器设置修改下的解聚情况，清楚地表明了单体去除对反应的高度有利影响。所采用的方法通过降低溶剂使用量、扩大其温度操作窗口并使聚合物含量达到实际相关水平，朝着甲基丙烯酸酯解聚的工业可行性迈出了重要一步。
