POLYPHENYLETHERKETONE AND POLYPHENYLETHERSULFONE ADHESIVES FOR METAL-TO-METAL JOINTS

Two major factors play an important part in improving adhesive bonding in crystalline polyphenyletherketone (PEK) and amorphous polyphenylet hersulfone (PES) polymer-to-metal joint systems: (1) the mechanical st rength of reaction product layers formed at polymer/metal interfaces i s greater than that of the polymer itself; and (2) the extent of mecha nically weak Fe2O3 layers on interfacial metal surfaces, which should be minimized to avoid the undesirable cohesive failure mode through th ese layers. As a result, the most promising failure mechanism for good bond performance was the mixed cohesive failure modes in which separa tion occurred in both the polymer and adhesive layers at the polymer/m etal interfaces.