High-Strength, Healable, Supramolecular Polymer Nanocomposites
High-Strength, Healable, Supramolecular Polymer Nanocomposites
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DOI：
10.1021/ja300050x
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发表时间：
2012-03-21
影响因子：
15
通讯作者：
Rowan, Stuart J.
中科院分区：
文献类型：
--
作者：
Fox, Justin;Wie, Jeong J.;Rowan, Stuart J.
通过富含π电子的芘基封端低聚物和含有成对π电子贫萘二酰亚胺（NDI）单元的链折叠低聚物之间的π-π相互作用形成的超分子聚合物共混物已用纤维素纳米晶体（CNC）增强，以提供可修复的纳米复合材料。通过溶剂浇铸和压缩成型制备了可修复超分子聚合物基质中具有不同重量百分比的 CNC（1.25 至 20.0 wt%）的纳米复合材料，并评估了它们的机械性能和修复行为。研究发现，CNC 含量低于 10 wt% 时可以形成均匀分散的薄膜。获得了超过 10 wt% CNC 异质纳米复合材料。所有形成的纳米复合材料在暴露于高温时都可以重新愈合，但对于均质薄膜，发现愈合率随着 CNC 含量的增加而降低。 7.5 wt% CNC 纳米复合材料获得了愈合效率和机械性能的最佳组合，其拉伸模量比单独的基体材料提高了 20 倍，并且可以在 85 摄氏度下在 30 毫米内完全重新愈合。因此，这证明超分子纳米复合材料相对于未增强的聚合物可以提供大大增强的机械性能，同时仍然允许有效的热修复。
A supramolecular polymer blend, formed via pi-pi interactions between a pi-electron rich pyrenyl end-capped oligomer and a chain-folding oligomer containing pairs of pi-electron poor naphthalene-diimide (NDI) units, has been reinforced with cellulose nanocrystals (CNCs) to afford a healable nanocomposite material. Nanocomposites with varying weight percentage of CNCs (from 1.25 to 20.0 wt %) within the healable supramolecular polymeric matrix have been prepared via solvent casting followed by compression molding, and their mechanical properties and healing behavior have been evaluated. It is found that homogeneously dispersed films can be formed with CNCs at less than 10 wt %. Above 10 wt % CNC heterogeneous nanocomposites were obtained. All the nanocomposites formed could be rehealed upon exposure to elevated temperatures although, for the homogeneous films, it was found that the healing rate was reduced with increasing CNC content. The best combination of healing efficiency and mechanical properties was obtained with the 7.5 wt % CNC nanocomposite which exhibited a tensile modulus enhanced by as much as a factor of 20 over the matrix material alone and could be fully rehealed at 85 degrees C within 30 mm. Thus it is demonstrated that supramolecular nanocomposites can afford greatly enhanced mechanical properties relative to the unreinforced polymer, while still allowing efficient thermal healing.