Nanostructured biocomposites of high toughness—a wood cellulose nanofiber network in ductile hydroxyethylcellulose matrix
Nanostructured biocomposites of high toughness—a wood cellulose nanofiber network in ductile hydroxyethylcellulose matrix
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高韧性纳米结构生物复合材料——延展性羟乙基纤维素基质中的木质纤维素纳米纤维网络
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发表时间：
2011
期刊：
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通讯作者：
L. Berglund
中科院分区：
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作者：
H. Sehaqui;Qi Zhou;L. Berglund
与基于植物纤维的纸和植物纤维生物复合材料相比，基于木材的纳米原纤化纤维素（NFC）的纳米纸提供了大大改善的强度和断裂应变。在本研究中，独特的纳米结构的增韧效果，纤维素纤维素/羟乙基纤维素（HEC）生物复合材料的报告。HEC是高摩尔质量和韧性的无定形纤维素衍生物。以前开发的制备路线的灵感来自造纸。它是“绿色”的、可扩展的，并且允许高的增强内容。在本概念中，当聚合物与增强物缔合时，实施聚合物基质分布的纳米结构控制。这导致在纳米原纤化纤维素周围的软HEC基质的纳米复合材料形成亚微米级的层压结构，如FE-SEM所观察到的。我们研究了NFC体积分数对纳米复合材料的拉伸性能、热机械稳定性、蠕变性能和吸湿性能的影响。结果表明，由于NFC网络的承载能力，NFC内容的性能得到了很大的改善。在45%的NFC体积分数下，与纤维素纳米纸相比，韧性增加了一倍以上。本发明的纳米复合材料位于先前未被占据的空间中，在强度与应变失效特性图中，在由微尺度复合材料和工程聚合物占据的区域之外。研究结果强调了基于高体积分数纳米纤维网络的纳米结构生物复合材料所提供的扩展复合材料力学性能范围的潜力。
Nanopaper from wood-based nanofibrillated cellulose (NFC) offers vastly improved strength and strain-to-failure compared with plant fiber-based paper and plant fiber biocomposites. In the present study, unique nanostructural toughening effects are reported in cellulose nanofiber/hydroxyethylcellulose (HEC) biocomposites. HEC is an amorphous cellulose derivative of high molar mass and toughness. A previously developed preparation route inspired by paper-making is used. It is “green”, scalable, and allows high reinforcement content. In the present concept, nanostructural control of polymer matrix distribution is exercised as the polymer associates with the reinforcement. This results in nanocomposites of a soft HEC matrix surrounding nanofibrillated cellulose forming a laminated structure at the submicron scale, as observed by FE-SEM. We study the effect of NFC volume fraction on tensile properties, thermomechanical stability, creep properties and moisture sorption of the nanocomposites. The results show strong property improvements with NFC content due to the load-carrying ability of the NFC network. At an NFC volume fraction of 45%, the toughness was more than doubled compared with cellulose nanopaper. The present nanocomposite is located in previously unoccupied space in a strength versus strain-to-failure property chart, outside the regions occupied by microscale composites and engineering polymers. The results emphasize the potential for extended composites mechanical property range offered by nanostructured biocomposites based on high volume fraction nanofiber networks.