A versatile approach for the synthesis of degradable polymers via controlled ring-opening metathesis copolymerization
A versatile approach for the synthesis of degradable polymers via controlled ring-opening metathesis copolymerization
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DOI：
10.1038/s41557-021-00810-2
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发表时间：
2021-11-18
期刊：
影响因子：
21.8
通讯作者：
Xia, Yan
中科院分区：
文献类型：
--
作者：
Feist, John D.;Lee, Daniel C.;Xia, Yan
降冰片烯衍生物(NBE)是活性开环歧化聚合的常用单体，具有分散性低、官能化程度高等特点。然而，聚NBE的全碳骨架是不可降解的。本文报道了一种通过2，3-二氢呋喃与NBES共聚合成可降解聚合物的方法。2，3-二氢呋喃与格拉布斯催化剂快速反应生成热力学稳定的Ru-Fischer卡宾--共聚过程中唯一可检测到的活性Ru物种--NBE的加入成为速率决定因素。这种反应性减弱了NBE的同加成反应，并允许在整个共聚物中均匀地加入可酸降解的烯醇醚键，这使得聚合物能够完全降解，同时保持了活性开环易位聚合的有利特性。通过2，3-二氢呋喃与NBES的共聚反应，得到了具有可调溶解度、玻璃化转变温度和力学性能的低分散性聚合物。这些聚合物可以在温和的酸性条件下完全降解为小分子或低聚物。这种方法可以很容易地适用于广泛使用的NBE的传统开环歧化聚合，以合成性能可调的易降解聚合物，用于各种应用和环境可持续性。
Norbornene derivatives (NBEs) are common monomers for living ring-opening metathesis polymerization and yield polymers with low dispersities and diverse functionalities. However, the all-carbon backbone of poly-NBEs is non-degradable. Here we report a method to synthesize degradable polymers by copolymerizing 2,3-dihydrofuran with NBEs. 2,3-Dihydrofuran rapidly reacts with Grubbs catalyst to form a thermodynamically stable Ru Fischer carbene-the only detectable active Ru species during copolymerization-and the addition of NBEs becomes rate determining. This reactivity attenuates the NBE homoaddition and allows uniform incorporation of acid-degradable enol ether linkages throughout the copolymers, which enables complete polymer degradation while maintaining the favourable characteristics of living ring-opening metathesis polymerization. Copolymerization of 2,3-dihydrofuran with NBEs gives low dispersity polymers with tunable solubility, glass transition temperature and mechanical properties. These polymers can be fully degraded into small molecule or oligomeric species under mildly acidic conditions. This method can be readily adapted to traditional ring-opening metathesis polymerization of widely used NBEs to synthesize easily degradable polymers with tunable properties for various applications and for environmental sustainability.