Hou Yue, Feng Jing, Tian Rui, Lu Chao, Duan Xue
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China.
Angew Chem Int Ed Engl. 2023 Sep 11;62(37):e202307573. doi: 10.1002/anie.202307573. Epub 2023 Aug 4.
Understanding the radical behaviours during polymer degradation is beneficial to unveil and regulate the degradation pathways of polymers to achieve a sustainable polymer development. However, it is a long-standing challenge to study radical behaviours owing to the ultra-short lifetime of the transient radicals generated during the polymer degradation. In this contribution, we have proposed the radical-triggered luminescence to monitor the radical behaviours during polymer degradation without/with the addition of inorganic additives. It was disclosed that the pure polymers showed a single sigmoidal dynamic curve from peroxy radicals (ROO⋅) emissions, leading to the exponential proliferation for the degradation evolution. Alternatively, the degradation pathways with the addition of additives, layered double hydroxides (LDHs) with positively charged Al centers, could be modulated into a double sigmoidal dynamics, involving the main product of alkoxy radicals (RO⋅) with the activation energy of 40.2 kJ/mol and a small amount of ROO⋅ with 76.3 kJ/mol, respectively. Accordingly, the polymers with the additive-regulated pathways could exhibit prominently anti-degradation behaviours. This work is beneficial for the deep understanding of the radical mechanisms during polymer degradation, and for the rational design of anti-degradation polymers.
了解聚合物降解过程中的自由基行为有助于揭示和调控聚合物的降解途径，以实现聚合物的可持续发展。然而，由于聚合物降解过程中产生的瞬态自由基寿命极短，研究自由基行为一直是一项长期挑战。在本论文中，我们提出了自由基触发发光法来监测聚合物降解过程中的自由基行为，该方法无需添加/添加无机添加剂。结果表明，纯聚合物呈现出由过氧自由基（ROO⋅）发射产生的单S形动力学曲线，导致降解过程呈指数增长。相反，添加添加剂（带正电荷Al中心的层状双氢氧化物（LDHs））后的降解途径可被调控为双S形动力学，分别涉及活化能为40.2 kJ/mol的烷氧基自由基（RO⋅）的主要产物和少量活化能为76.3 kJ/mol的ROO⋅。因此，具有添加剂调控途径的聚合物可表现出显著的抗降解行为。这项工作有助于深入理解聚合物降解过程中的自由基机制，并有助于合理设计抗降解聚合物。
