Overcoming the Low Driving Force in Forming Depolymerizable Polymers through Monomer Isomerization
Overcoming the Low Driving Force in Forming Depolymerizable Polymers through Monomer Isomerization
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DOI：
10.1002/anie.202111181
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发表时间：
2021-10-25
影响因子：
16.6
通讯作者：
Wang, Junpeng
中科院分区：
文献类型：
--
作者：
Chen, Hanlin;Shi, Zhen;Wang, Junpeng
虽然可解聚聚合物作为一种潜在的解决方案已被广泛研究，以解决聚合物可持续发展的挑战，但大多数解聚系统的特点是聚合驱动力低，这给获得不同功能和结构的聚合物带来了困难。在这里，我们通过使用基于环辛烯的解聚体系来解决这一挑战，在该体系中，顺式到反式烯烃的异构化显著增加了环应变能，以实现单体浓度为>；=0.025 M的活性开环歧化聚合。另外，在环辛烯的5，6位融合的反式环丁烷降低了环辛烯的环应变能，使相应的聚合物能够解聚成顺式环辛烯单体。过量的三苯基膦的使用被发现对于抑制二次歧化和解聚是必不可少的。反式环丁烷稠合反式环辛烯体系的高驱动力活性聚合为开发各种聚合物结构的可化学回收聚合物提供了前景。
While depolymerizable polymers have been intensely pursued as a potential solution to address the challenges in polymer sustainability, most depolymerization systems are characterized by a low driving force in polymerization, which poses difficulties for accessing diverse functionalities and architectures of polymers. Here, we address this challenge by using a cyclooctene-based depolymerization system, in which the cis-to-trans alkene isomerization significantly increases the ring strain energy to enable living ring-opening metathesis polymerization at monomer concentrations >= 0.025 M. An additional trans-cyclobutane fused at the 5,6-position of the cyclooctene reduces the ring strain energy of cyclooctene, enabling the corresponding polymers to depolymerize into the cis-cyclooctene monomers. The use of excess triphenylphosphine was found to be essential to suppress secondary metathesis and depolymerization. The high-driving-force living polymerization of the trans-cyclobutane fused trans-cyclooctene system holds promise for developing chemically recyclable polymers of a wide variety of polymer architectures.