Kinetic study of photoinitiated grafting of diallyl oxydiethylene dicarbonate onto cellulose

Photochemical grafting of diallyl oxydiethylene dicarbonate onto cellulose (in the form of filter paper) was investigated kinetically at 20 ± 2 °C with 1,2-diphenyl-2,2-dimethoxyethanone as photoinitiator. Irradiations were carried out polychromatically with an incident radiation flux of (1.25 ± 0.07) × 10-7 einstein s-1 cm-2. The ratio R between the molar concentrations of photoinitiator and monomer was varied in the range 0.032-0.150 and the n/S value (n moles of monomer adsorbed per unit apparent surface S) was varied in the range 8.40-43.8 μmol cm-2. Two consecutive rate processes were shown by the kinetic curves, with quantum yields differing by about two orders of magnitude. Quantum yields Φ1 for the first, almost constant, rate period were measured as a function of R and n/S. Kinetic features of the grafting process of diallylic monomer are discussed in the light of a general mechanism proposed for grafting of diacrylates and the photochemical reactivity of the allylic vs. the acrylic function.