Three-dimensional polymer composites offer various features and design options due to their hollow structure and lightweight. However, to exploit their advantages, it is a must to improve their structural features and mechanical performances including out-plane direction. Although introducing thermoplastic fillers between the plies or multilayered design addresses on this critical issue, the benefits offered by the nanoparticles with superior mechanical properties come a step forward as an another engineering solution. Based on this motivation, the goal of this study is to investigate the impact of multiwalled carbon nanotubes on the mechanical and thermomechanical performances of three-dimensional woven glass/epoxy spacer composites. Therefore, multiwalled carbon nanotubes at various content were introduced into epoxy matrix, and the multiwalled carbon nanotubes–epoxy mixture was infused to three-dimensional woven fabric with the vacuum-assisted resin transfer method. The obtained results indicated that the three-point bending strength and modulus were enhanced up to 25 and 80% for warp direction and enhanced up to 44 and 85% for weft direction with carbon nanotube addition, respectively. Tensile strength developed in the warp direction by 7%, while the strength value in the weft direction did not change. The tensile strain values for warp and weft directions enhanced up to 19 and 12% with carbon nanotube addition, respectively. In addition, thermomechanical analysis has revealed that the glass transition temperature and storage modulus were also improved. Particle dispersion detection with color measurement and scanning electron microscopy analyses revealed the effectiveness of the ultrasonic mixing on the dispersion of carbon nanotubes in the epoxy matrix. The consequences of carbon nanotube addition on microscale morphology were discussed based on the fracture morphologies to nanoscale and microscale toughening mechanisms in the existence of carbon nanotube reinforcement.

三维聚合物复合材料由于其空心结构和轻巧性而提供了多种功能和设计选择。但是，要利用它们的优点，必须改善它们的结构特征和机械性能，包括平面方向。尽管在此关键问题之间引入了热塑性填料，但解决了这一关键问题，具有优异机械性能的纳米颗粒所带来的好处还是作为另一种工程解决方案向前迈进了一步。基于这种动机，本研究的目的是研究多壁碳纳米管对三维机织玻璃/环氧树脂垫片复合材料的机械和热机械性能的影响。因此，将各种含量的多壁碳纳米管引入环氧基体中，然后用真空辅助树脂转移法将多壁碳纳米管-环氧树脂混合物注入三维机织织物中。获得的结果表明，添加碳纳米管分别使经向的三点弯曲强度和模量提高了25％和80％，而纬向的三点弯曲强度和模量分别提高了44％和85％。拉伸强度在经纱方向上增加了7％，而在纬纱方向上的强度值没有变化。添加碳纳米管后，经向和纬向的拉伸应变值分别提高了19％和12％。另外，热力学分析表明玻璃化转变温度和储能模量也得到改善。通过颜色测量和扫描电子显微镜分析进行的颗粒分散检测表明，超声混合对碳纳米管在环氧基质中的分散有效。在存在碳纳米管增强剂的情况下，基于断裂形貌对纳米尺度和微观尺度的增韧机理，讨论了碳纳米管添加对微观尺度形态的影响。