PHOTOCHEMICAL SURFACE MODIFICATION OF POLYPROPYLENE FOR ADHESION ENHANCEMENT BY USING AN EXCIMER-LASER

Polypropylene (PP) surface in water was photochemically modified to re nder it hydrophilic using ArF excimer laser radiation. The chemical st ability of PP is attributed to the C-H and C-H-3 bonds present. Thus, it is considered that H atoms are selectively pulled out from the area irradiated with ArF excimer laser light and are replaced with OH func tional groups in the presence of water. In this treatment, the irradia ted sample becomes hydrophilic with enhanced adhesion properties. The experimental conditions for this surface treatment were ArF laser flue nce of 12.5 mJ/cm(2) and a shot number of 10000. The treated PP and st ainless steel were bonded with epoxy adhesive and the tensile shear st rength was 46 kg/cm(2).