Photochemical grafting of acrylated azo dyes onto polymeric surfaces. VII. Kinetics and mechanism of dye‐sensitized photoinitiation of some diacrylates

摘要

AbstractPhotoinitiated 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 ± 2°C. Irradiation was carried out polychromatically, with impinging photoenergy from 2.1 × 10−8to 20.5 × 10−8einstein s−1cm−2; in some of the runs the ultraviolet radiation was filtered. The ratioRbetween the molar concentration of photoinitiator and the sum of concentrations of dye and diacrylate varied between 0.005 and 0.095; the ratioMbetween the molar concentration of dye and diacrylate varied between 0.005 and 0.046. The moles of dye and diacrylateninitially deposited per unit apparent polymeric surfaceSvaried between 2 and 74 μmol cm−2.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