Size effect of graphene nanoparticle modified epoxy matrix
Size effect of graphene nanoparticle modified epoxy matrix
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DOI：
10.1016/j.compscitech.2016.08.022
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发表时间：
2016-10-06
影响因子：
9.1
通讯作者：
Fiedler, Bodo
中科院分区：
文献类型：
--
作者：
Leopold, Christian;Liebig, Wilfried V.;Fiedler, Bodo
实验研究了未改性和石墨烯纳米颗粒改性基体纤维的尺寸效应。由于统计缺陷分布，纯基质纤维显示出明显的尺寸效应，即抗拉强度随着体积的减小而增加。纳米粒子改性的基质没有显示出显著的尺寸效应。纳米颗粒充当裂纹引发剂并消耗断裂能。颗粒的尺寸与试样体积无关，因此失效启动和能量吸收机制与体积无关。SEM图像的断口分析显示了不同的能量耗散机制，例如石墨烯颗粒处的微损伤。观察到石墨烯拉出、层分离、层剪切、微空隙的形成以及裂纹分离和裂纹分叉，这取决于石墨层相对于断裂平面的取向。这些机制耗散能量，并且使得石墨烯纳米颗粒改性导致断裂韧性增加，并且因此如果体积足够大，则导致环氧树脂基质系统的强度增加。小体积试样中的最大应力取决于石墨烯层取向，因此理想情况下，纳米颗粒的共价键应沿加载方向取向。(C)2016作者由爱思唯尔有限公司出版。这是一篇在CC BY-NC-ND许可证下的开放获取文章（http：//creativecommons.org/licenses/by-nc-nd/4.0/）。
The size effect of unmodified and graphene nanoparticle modified matrix fibres is experimentally investigated. Neat matrix fibres show a clear size effect of increasing tensile strength with decreasing volume due to a statistical defect distribution. The nanoparticle modified matrix shows no significant size effect. Nanoparticles act as crack initiators and consume fracture energy. The size of the particles is independent of specimen volume, so that the failure initiating as well as energy absorbing mechanisms are available, independently of the volume. Fractography analysis of SEM images shows different energy dissipation mechanisms such as micro-damage at the graphene particles. Graphene pull-out, layer separation, layer shearing, formation of micro voids as well as crack separation and crack bifurcation are observed that depend on the orientation of the graphite layers to the fracture plane. These mechanisms dissipate energy and so that a graphene nanoparticle modification result in an increased fracture toughness and thus increased strength of an epoxy matrix system if the volume is large enough. The maximum stress in specimen of small volume depends on graphene layer orientation, so that ideally, the covalent bonds of the nanoparticles should be orientated in loading direction. (C) 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).