High strength/toughness nanocomposites are increasingly in demand due to the development needs of high-end applications. However, the aggregation and random orientation of nanofillers and the weak crosslinking of the polymer matrix lead to the degradation of the mechanical properties of nanocomposites. Here, we present a strategy to prepare chitosan-based nanocomposites with aligned nanosheets via the in situ photo-crosslinking of modified chitosan. The well-dispersed and highly aligned nanosheets, as well as the dense covalently crosslinked network between the modified chitosan chains, effectively improve the mechanical properties of the prepared nanocomposites. For example, the chitosan-based nanocomposite films exhibit a tensile strength of up to 340.6 ± 13.4 MPa, a Young's modulus of 8.2 ± 0.2 GPa and a toughness of 22.0 ± 2.5 MJ m⁻³, which are 4.2, 4.8 and 1.8 times higher, respectively, than those of pure chitosan films. Moreover, the thermal decomposition temperature of the chitosan-based nanocomposite films reaches 286.8 °C, which is 48.5 °C higher than that of pure chitosan films. We consider that our strategy, which constructs a crosslinked chitosan structure with aligned nanofillers, could lead to the development and application of the bio-based composites with excellent mechanical properties.

中文翻译：

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具有对齐纳米片和交联网络的高强度壳聚糖基纳米复合材料


由于高端应用的发展需求，高强度/韧性纳米复合材料的需求越来越大。然而，纳米填料的聚集和随机取向以及聚合物基体的弱交联导致纳米复合材料的机械性能下降。在这里，我们提出了一种策略，通过改性壳聚糖的原位光交联制备具有对齐纳米片的壳聚糖基纳米复合材料。分散良好且高度对齐的纳米片，以及改性壳聚糖链之间密集的共价交联网络，有效改善了所制备的纳米复合材料的机械性能。例如，壳聚糖基纳米复合薄膜表现出高达 340.6 ± 13.4 MPa 的拉伸强度、8.2 ± 0.2 GPa 的杨氏模量和 22.0 ± 2.5 MJ ^m-3 的韧性，分别是纯壳聚糖薄膜的 4.2、4.8 和 1.8 倍。此外，壳聚糖基纳米复合薄膜的热分解温度达到 286.8 °C，比纯壳聚糖薄膜高 48.5 °C。我们认为，我们的策略是用对齐的纳米填料构建交联壳聚糖结构，这可能会导致具有优异机械性能的生物基复合材料的开发和应用。