PHOTOCHEMICAL GRAFTING OF ACRYLATED AZO DYES ONTO POLYMERIC SURFACES .7. KINETICS AND MECHANISM OF DYE-SENSITIZED PHOTOINITIATION OF SOME DIACRYLATES

Photoinitiated grafting and graft polymerization of liquid mixtures, adsorbed onto polypropylene, polycaprolactam, and poly(ethylene terephthalate) films, containing one of four acryloxy-substituted aromatic diazenes and one of four diacrylate comonomers, in the presence of 1,2-diphenyl-2,2-dimethoxyethanone as photoinitiator, were investigated kinetically at 30 plus or minus 2 degree C. Irradiation was carried out polychromatically, with impinging photoenergy from 2. 1 multiplied by 10** minus 8 to 20. 5 multiplied by 10** minus 8 einstein s** minus 1 cm** minus 2; in some of the runs the ultraviolet radiation was filtered. No selective effect was shown by the presence of dyes in the comonomer mixture. The surface density of grafted molecules at the end of the grafting process was not affected by the photoinitiator concentration (for 0. 030 less than R less than 0. 095), by diacrylate or dye concentrations, or by the kind of polymer substrate.