Adhesion of microwave‐plasma‐treated fluoropolymers to thermoset vinylester

Poly(tetrafluoroethylene) and a fluoroethylene copolymer were surface treated with a 2.45‐GHz microwave plasma to enhance their adhesion to a vinylester thermoset. The plasmas were generated with an inert gas (Ar) and with reactive gases (H 2 , O 2 , and N 2 ). The lap‐joint shear stress was measured on fluoropolymer samples glued with the vinylester. In general, the stress at failure increased with increasing plasma‐energy dose. The H 2 plasma yielded the best adhesion, and X‐ray photoelectron spectroscopy revealed that it yielded the highest degree of defluorination of the fluoropolymer surface. The defluorination efficiency declined in the order H 2 , Ar, O 2 , and N 2 . Contact angle measurements and scanning electron microscopy revealed that the surface roughness of the fluoropolymer depended on the rate of achieving the target energy dose. High power led to a smoother surface, probably because of a greater increase in temperature and partial melting. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 838–842, 2005