Fricke Sophia N, Salgado Mia, Haber Shira, Demarteau Jeremy, Hua Mutian, Song Ah-Young, Helms Brett A, Reimer Jeffrey A
Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA.
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Sci Adv. 2025 Apr 11;11(15):eadt6144. doi: 10.1126/sciadv.adt6144.
Chemical recycling of commodity and specialty polymers presents a multifaceted challenge for industrial societies. On one hand, macromolecular architectures must be engineered to yield durable products that, on the other hand, rapidly deconstruct to recyclable monomers under pre-determined conditions. Polymer deconstruction is a chemical process that requires deep understanding of molecular reactivity in heterogeneous media, where porous material architectures evolve in both space and time. To build this understanding, we develop herein experimental and analytical methods describing sets of diffusive eigenmodes that exist within time-varying, non-Euclidean boundary conditions, a situation commonly encountered in the reactive deconstruction of polymers where chain fragments splay, alter their local dynamics, and evolve in their confinement of reacting media. Diffusion power spectra, discerned experimentally by NMR, yield polymer and solvent frequency-domain velocity autocorrelation functions that are analyzed in the context of physical models for chemical reactions parameterized with fractal mathematics. The results connect local motion in polymers to chemical reactivity during acidolysis of circular elastomers.
商品聚合物和特种聚合物的化学循环利用给工业社会带来了多方面的挑战。一方面，必须设计高分子结构以生产耐用产品，而另一方面，这些产品要在预定条件下迅速分解为可回收的单体。聚合物解构是一个化学过程，需要深入了解非均相介质中的分子反应性，在这种介质中，多孔材料结构会随时间和空间演变。为了建立这种理解，我们在此开发了实验和分析方法，用于描述在随时间变化的非欧几里得边界条件下存在的一组扩散本征模，这种情况在聚合物的反应解构中很常见，其中链片段会展开、改变其局部动力学，并在反应介质的限制中演化。通过核磁共振实验辨别出的扩散功率谱，产生了聚合物和溶剂的频域速度自相关函数，这些函数在用量子数学参数化的化学反应物理模型的背景下进行分析。结果将聚合物中的局部运动与圆形弹性体酸解过程中的化学反应性联系起来。
