Injection-molded samples of polypropylene were exposed to oxygen plasma and
SACO (SAndblasting and COating) treatments. The pretreated surfaces were s
uccessively adhesively bonded or lacquered. The adhesion strength and failu
re mode of these specimens were examined. The surfaces obtained after treat
ments were characterized by electron spectroscopy for chemical analysis (ES
CA), contact angle measurements, and scanning electron microscopy (SEM). Bo
th microroughness and chemical modification of the surface led to an increa
se in adhesion by up to a factor of 10. The stability of the surface change
s generated during the plasma and SACO pretreatments was observed by differ
ent kinds of aging experiments in air and water. The aging of SACO-treated
surfaces led to no significant change on the surface. In the case of plasma
-treated surfaces, hydrophobic recovery during aging in air reduced the pol
arity of the surface layer. During aging in water, no hydrophobic recovery
on the surface was observed.