The Influence of Moisture Absorption-Drying of Composite Materials on the Bonding Performance of the Joints

Composite materials are susceptible to environmental threats correlated to moisture absorption, which affects the bonding performance of the joints. Therefore, drying should be taken into account during actual manufacturing operations. In this work, the influence of moisture absorption-drying of composite materials on the bonding performance of the joints is investigated to provide a theoretical direction for the co-bonding process. Firstly, the surfaces of composite materials are treated with three methods: sanding, dry peel ply, and wet peel ply. Secondly, the composite materials are subjected to moisture absorption-drying treatment at 26 °C/65% relative humidity (RH) and 70 °C/85% RH. Finally, the above materials are bonded to evaluate the bonding performance. These results show that the bonding performance of the joints treated with two peel plies decreases significantly after moisture absorption. After moisture absorption-drying at 26 °C/65% RH, the bonding performance of the joints treated with dry peel ply cannot fully recover, while wet peel ply can be fully recoverable. However, the bonding performance of all joints cannot fully recover after absorbing moisture-drying at 70 °C/85% RH, whose recovery has relations with surface treatment.