High-Field Nuclear Magnetic Resonance Studies Reveal New Structural Landscape of Sulfur-Vulcanized Natural Rubber,Biomacromolecules

当前位置： X-MOL 学术 › Biomacromolecules › 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.)

High-Field Nuclear Magnetic Resonance Studies Reveal New Structural Landscape of Sulfur-Vulcanized Natural Rubber
Biomacromolecules ( IF 5.5 ) Pub Date : 2022-10-24 , DOI: 10.1021/acs.biomac.2c00141
Kousuke Kashihara _{1,

2} , Muneki Oouchi _{1,

2} , Yu Kodama ₁ , Tatsuhiro Arai ₁ , Miki Horie _{3,

4} , Takehiro Kitaura ₃ , Yoshitaka Ishii _{1,

2,

5}

Affiliation

Despite intensive research efforts over the past 3 decades, the structural analysis of sulfur-vulcanized natural rubber (NR) remains challenging owing to the complexity and low population of its sulfur moieties. Herein, solid vulcanized NR samples and NR samples reacted with sulfur and other reactants in an organic solvent were analyzed by solid-state NMR with fast magic-angle spinning and solution NMR, respectively. The present high-field two-dimensional NMR analysis revealed six novel sulfur moieties in these samples, including cyclic sulfides, cyclic di/polysulfides, and crosslinked structures with a vinylidene group. While previous studies reported a variety of sulfur-crosslinked structures in NR, our analysis identified only two dominant types of crosslinked structures that matched those reported previously. Our NMR assignments for the crosslinked structures were inconsistent to a large extent with those presented in the previous studies; thus, in the current work, the crosslinked structures were reassigned using the new data. Based on quantitative NMR analysis, this study also provides the first tangible evidence that cyclic rather than crosslinked sulfides can be the dominant sulfur moieties in vulcanized NR. These results may drastically alter the previously established structural landscape of sulfur-vulcanized NR.

中文翻译：

高场核磁共振研究揭示了硫硫化天然橡胶的新结构景观

尽管过去 3 年进行了大量研究，但由于硫部分的复杂性和低数量，硫硫化天然橡胶 (NR) 的结构分析仍然具有挑战性。在此，固体硫化 NR 样品和在有机溶剂中与硫和其他反应物反应的 NR 样品分别通过具有快速魔角旋转的固态 NMR 和溶液 NMR 进行分析。目前的高场二维 NMR 分析揭示了这些样品中的六个新硫部分，包括环状硫化物、环状二/多硫化物和具有亚乙烯基的交联结构。虽然之前的研究报告了 NR 中的各种硫交联结构，但我们的分析仅确定了两种与之前报告的相匹配的主要类型的交联结构。我们对交联结构的核磁共振分配在很大程度上与之前研究中提出的不一致；因此，在目前的工作中，使用新数据重新分配了交联结构。基于定量 NMR 分析，该研究还提供了第一个切实证据，证明硫化 NR 中的主要硫部分可能是环状硫化物而非交联硫化物。这些结果可能会极大地改变先前建立的硫硫化 NR 的结构景观。这项研究还提供了第一个切实的证据，表明环状而非交联的硫化物可能是硫化 NR 中的主要硫部分。这些结果可能会极大地改变先前建立的硫硫化 NR 的结构景观。这项研究还提供了第一个切实的证据，表明环状而非交联的硫化物可能是硫化 NR 中的主要硫部分。这些结果可能会极大地改变先前建立的硫硫化 NR 的结构景观。

更新日期：2022-10-24

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