SURFACE MODIFICATION OF POLYMER FIBERS BY UV LASER IRRADIATION .11. SURFACE MODIFICATION OF POLYPROPYLENE FIBERS AND FABRIC

It is shown that weakly UV-absorbing polymers like polypropylene (PP) become amenable to laser treatment by impregnation with strong absorbers like benzophenone. The high absorption coefficients of the doped polyolefines allow an efficient etching by laser irradiation. In addition, roll-like structures of the surface are obtained as they are known from laser-treatment of polyester and polyamide fibers. The dimensions of these structures on fibers are in the region of 10 to 25-mu-m with a depth of about 3-mu-m. Using biaxially stretched PP-foils, drop-like structures are obtained, thus indicating a predominance of thermal effects. On weakly absorbing systems like dyed PP-fibers only fusions of single filaments are obtainable. By mechanical contact of an undoped PP-foil with poly(ethyleneterephthalate) (PETP) foils laser irradiation creates roll-like structures on the PP-surface.