ADHESION STUDIES OF FLUOROPOLYMERS

A comparative study of the treatment of polytetrafluoroethylene (PTFE) and poly(vinyl fluoride) (PVF) with ''Tetra-Etch'' has been carried o ut. The treatment of PTFE resulted in extensive changes in surface che mistry and topography, whereas with PVF there was no significant chang e in topography and the chemical changes were much less marked. Howeve r, treatment of both polymers resulted in large increases in bond stre ngth. Multiple bonding experiments in which samples are repeatedly fra ctured and re-bonded were carried out with untreated PTFE and PVF. The se resulted in moderate increases in bond strength with PTFE and large increases with PVF. The results indicate that weak boundary layer (WB L) removal is a key element in adhesion improvement by ''Tetra-Etch'' on PVF. With PTFE, WBL removal also improves adhesion, but the chemica l and/or topographical changes introduced by the ''Tetra-Etch'' are re quired for optimum performance.