Breaking the Paradox between Grafting-Through and Depolymerization to Access Recyclable Graft Polymers
Breaking the Paradox between Grafting-Through and Depolymerization to Access Recyclable Graft Polymers
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DOI：
10.1021/acs.macromol.2c01609
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发表时间：
2022-10-14
期刊：
影响因子：
5.5
通讯作者：
Wang, Junpeng
中科院分区：
文献类型：
--
作者：
Wang, Zeyu;Yoon, Seiyoung;Wang, Junpeng
接枝聚合物由于其接枝结构而具有可用于广泛应用的独特性质。由于对循环经济的需求，期望具有可解聚的接枝聚合物。然而，可解聚的接枝聚合物是罕见的，并且可解聚的接枝聚合物的现有实例在控制尺寸和结构方面缺乏严格性。在本文中，我们展示了一种稳健的方法来合成可解聚的接枝聚合物，通过利用我们最近开发的由反式环丁烷稠合的反式环辛烯的受控开环易位聚合制备的化学可回收聚合物。高度应变的反式环辛烯的上级反应性允许大分子单体的接枝通过成功地进行，使得能够优异地控制各种类型的侧链（包括聚（乙二醇）、聚丙交酯和脂肪族链）的主链长度。值得注意的是，以高转化率（>90%）和低分散度（D < 1.2）实现了14 000 kDa的分子量。受控聚合使得能够合成各种结构的接枝聚合物，包括嵌段和统计共聚物。解聚动力学研究表明，接枝聚合物通过解链机制解聚成顺式环辛烯大分子单体。可解聚接枝聚合物的多功能合成为具有不同材料特性的可持续热塑性塑料打开了大门。
Graft polymers, owing to their grafted structures, possess unique properties useful for a broad range of applications. Due to the demand for a circular economy, it is desirable to have graft polymers depolymerizable. However, depolymerizable graft polymers are rare, and existing examples of depolymerizable graft polymers lack the rigor in controlling the size and architecture. Herein, we demonstrate a robust method to synthesize depolymerizable graft polymers by leveraging our recent development of chemically recyclable polymers prepared from controlled ring-opening metathesis polymerization of trans-cyclobutane fused trans-cyclooctenes. The superior reactivity of the highly strained trans-cyclooctene allows grafting-through of macromonomers to be successfully conducted, empowering excellent control in backbone length for various types of sidechains, including a poly(ethylene glycol), a polylactide, and an aliphatic chain. Notably, an ultrahigh molecular weight of 14 000 kDa is achieved with high conversion (>90%) and low dispersity (D < 1.2). The controlled polymerization enables the synthesis of graft polymers of various architectures, including block and statistical copolymers. Kinetic studies of depolymerization show that the graft polymers depolymerize to the cis-cyclooctene macromonomers through an unzipping mechanism. The versatile synthesis of depolymerizable graft polymers opens the door to sustainable thermoplastics with diverse material properties.