Laponite-graphene oxide hybrid particulate filler enhances mechanical properties of cross-linked epoxy
Laponite-graphene oxide hybrid particulate filler enhances mechanical properties of cross-linked epoxy
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DOI：
10.1007/s10965-018-1461-2
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发表时间：
2018-02-01
影响因子：
2.8
通讯作者：
Patro, T. Umasankar
中科院分区：
文献类型：
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作者：
Chouhan, Devesh K.;Kumar, Arvind;Patro, T. Umasankar
锂皂石和氧化石墨烯 (LGO) 的新型混合物在水介质中通过超声处理然后溶剂蒸发制备而成，用于增强环氧树脂基体。使用两步溶剂辅助工艺将混合体系分散在液体环氧树脂中。流变学显示，悬浮液在加工阻隔方面的增强可忽略不计。小角 X 射线散射 (SAXS) 和显微镜的组合分析表明纳米填料在基质中均匀分散。根据 SAXS 研究推断，填料在聚合物基质中表现出分形维数。 LGO 含量低于 0.5 wt% 时，结构表现出表面分形；高于 0.5 wt% 时，复合材料表现出质量分形，表明随着填料含量的增加，复合材料从分散良好的复合材料转变为团聚的复合材料。该复合材料在各种机械性能方面表现出显着的改进。值得注意的是，在环氧树脂基体中仅添加 0.5 wt% LGO 时，弯曲强度和模量分别增加了约 23% 和约 29%，断裂韧性增加了约 23%。复合材料获得了玻璃化转变温度 (T-g) 的双峰分布以及 Tg 的改善。纳米填料的同时强化和增韧效应可以通过断口分析来解释。
A new hybrid of Laponite and graphene oxide (LGO), prepared in aqueous media by ultrasonication followed by solvent evaporation was used to reinforce epoxy matrix. The hybrid system was dispersed in liquid epoxy using a two-step solvent-assisted process. The suspensions showed negligible enhancements in processing barrier as revealed by rheology. A combinatorial analysis of small-angle x-ray scattering (SAXS) and microscopy suggested uniform dispersion of nanofillers in the matrix. The fillers showed fractal dimensions in polymer matrix as inferred from SAXS studies. Below 0.5 wt% LGO, the structure showed surface fractal and above 0.5 wt% the composites showed mass fractal, indicating a transformation from well-dispersed to agglomerated composites as the filler content increases. The composites exhibited substantial improvements in various mechanical properties. Notably, the flexural strength and modulus increased by similar to 23% and similar to 29%, respectively, with only 0.5 wt% LGO and the fracture toughness showed an increment of similar to 23% with 0.3 wt% LGO in epoxy matrix. A bimodal distribution of glass transition temperature (T-g) with improved Tg was obtained for the composites. The simultaneous strengthening and toughening effects of nanofillers are explained by means of fractography.