Monodisperse Cyclic Polymer Mechanochemistry: Scission Kinetics and the Dynamic Memory Effect with Ultrasonication and Ball-Mill Grinding,Journal of the American Chemical Society

当前位置： X-MOL 学术 › J. Am. Chem. Soc. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Monodisperse Cyclic Polymer Mechanochemistry: Scission Kinetics and the Dynamic Memory Effect with Ultrasonication and Ball-Mill Grinding
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2023-07-24 , DOI: 10.1021/jacs.3c04733
Jinkyung Noh ₁ , Mo Beom Koo ₁ , Jisoo Jung ₁ , Gregory I Peterson ₂ , Kyoung Taek Kim ₁ , Tae-Lim Choi ₃

Affiliation

A series of monodisperse cyclic and linear poly(d,l-lactide)s (c-PLA and l-PLA, respectively) were prepared with various degrees of polymerization (DP) using an iterative convergent synthesis approach. The absence of a molecular weight distribution provided us a chance to study their mechanochemical reactivity without obstructions arising from the size distribution. Additionally, we prepared l- and c-PLAs with identical DPs, which enabled us to attribute differences in scission rates to the cyclic polymer architecture alone. The polymers were subjected to ultrasonication (US) and ball-mill grinding (BMG), and their degradation kinetics were explored. Up to 9.0 times larger scission rates were observed for l-PLA (compared to c-PLA) with US, but the difference was less than 1.9 times with BMG. Fragmentation requires two backbone scission events for c-PLA, and we were able to observe linear intermediates (formed after a single scission) for the first time. We also developed a new method of studying the dynamic memory effect in US by characterizing and comparing the daughter fragment molecular weight distributions of l- and c-PLAs. These results provide new insights into the influence of the cyclic polymer architecture on mechanochemical reactions as well as differences in reactivity observed with US and BMG.

中文翻译：

单分散环状聚合物机械化学：超声波和球磨机研磨的断裂动力学和动态记忆效应

使用迭代收敛合成方法制备了一系列具有不同聚合度（DP）的单分散环状和线性聚（d，l-丙交酯）（分别为c -PLA和l -PLA）。分子量分布的缺失为我们提供了研究它们的机械化学反应性的机会，而不受尺寸分布的阻碍。此外，我们制备了具有相同DP的l-和c -PLA，这使我们能够将断裂率的差异单独归因于环状聚合物结构。对聚合物进行超声波处理（US）和球磨机研磨（BMG），并探讨了它们的降解动力学。US 观察到l -PLA的断裂率高达 9.0 倍（与c -PLA相比），但 BMG 的差异小于 1.9 倍。c -PLA的断裂需要两次主链断裂事件，我们首次能够观察到线性中间体（单次断裂后形成）。我们还通过表征和比较l - 和c - PLA的子片段分子量分布，开发了一种研究动态记忆效应的新方法。这些结果为环状聚合物结构对机械化学反应的影响以及 US 和 BMG 观察到的反应性差异提供了新的见解。

更新日期：2023-07-24

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南