ABSTRACT

The vulnerability of epoxy-based adhesives and resins to hygrothermal conditions limits their applicability in aggressive environments. Adhesives and resins are often exposed to repeated environmental conditions. In this paper, the effect of hydrophilic and hydrophobic nanofillers on the residual water, the coefficient of water diffusion, the strength and stiffness of nanocomposite adhesives under water absorption, desorption and resorption was experimentally studied. The results showed that by drying the wet samples, water was partially desorbed and a part of the degraded strength was recovered. Then, re-wetting the specimens resulted in further water absorption and material degradation at a much higher rate. The nanocomposites were made of epoxy resin, Fe₂O₃ nanoparticles and graphene oxide nanoplatelets (GONPs). The nanofillers decreased the water uptake after wetting, while increased the residual water after drying by confining water movement inside the material. Moreover, Fe₂O₃ nanoparticles and GONPs improved the fracture strength after water absorption by 28.8% and 22.3%, after water desorption by 54.4% and 42.2% and after water resorption by 40.2% and 29.3%, respectively. Furthermore, Fe₂O₃ nanoparticles and GONPs improved the strength recovery by 39.9% and 29.1%, respectively, compared to the neat epoxy.

摘要

环氧基粘合剂和树脂对湿热条件的脆弱性限制了它们在腐蚀性环境中的适用性。粘合剂和树脂经常暴露在重复的环境条件下。本文通过实验研究了亲水和疏水纳米填料对吸水、解吸和再吸水作用下纳米复合粘合剂的残留水、水扩散系数、强度和刚度的影响。结果表明，通过干燥湿样品，水分被部分解吸，部分退化的强度得到恢复。然后，重新润湿样品会导致进一步的吸水和材料以更高的速率降解。纳米复合材料由环氧树脂、Fe ₂ O _3制成纳米颗粒和氧化石墨烯纳米片（GONPs）。纳米填料在润湿后减少了水的吸收，同时通过限制材料内部的水运动增加了干燥后的残留水。此外，Fe ₂ O ₃纳米粒子和 GONPs 分别提高了吸水后的断裂强度 28.8% 和 22.3%，吸水后的断裂强度分别提高了 54.4% 和 42.2%，吸水后的断裂强度分别提高了 40.2% 和 29.3%。此外，与纯环氧树脂相比，Fe ₂ O ₃纳米颗粒和 GONP 分别将强度恢复提高了 39.9% 和 29.1%。