A KRF EXCIMER LASER-INDUCED DEHYDROCHLORINATION OF A CHLORINATED POLY(VINYL CHLORIDE) - PREPARATION OF CONJUGATED POLYENE AND POLYYNE

The photochemical dehydrochlorination of a chlorinated poly(vinyl chlo ride) film was investigated with respect to the preparation of a pi-el ectron-conjugated polymer. The dehydrochlorination proceeds more effec tively upon irradiation with a KrF excimer laser than with a low-press ure mercury lamp, showing the formation of new absorption bands in the range 300-800 nm. The most effective condition provided KrF excimer l aser irradiation of 25-30 mJ/cm2 at 1 Hz in a vacuum chamber of 10(-6) Torr at 90-degrees-C. The surface of the irradiated film was analyzed by IR (attenuated total reflection method), X-ray photoelectron and R aman spectroscopy. The characteristic peaks (1 112, 1 488 and 2 188 cm 1) in the Raman spectrum were ascribed to a structure having eight co njugated C = C bonds and twenty conjugated C = C bonds.