1 interface failure: the adhesive layer is separated from the surface of the adhesive body (complete detachment of the adhesive interface);
2 cohesive failure: the failure occurs in the adhesive or the adhesive body itself, but not in the adhesive interface between;
3 mixed damage: the adhesive and the adhesive layer itself is partially destroyed or the two are only one of them.
The damage that the bonding strength not only by force between the adherend and adhesive, and adhesive material between the polymer molecules is related to the interaction.
The chemical structure of polymer molecules, and the aggregation state strongly affect the bonding strength. It is very important for the design, synthesis and selection of adhesives to study the molecular structure of adhesive based materials.