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-degrees-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) x 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-mu-mol cm-2. Two consecutive rate processes were shown by the kinetic curves, with quantum yields differing by about two orders of magnitude. Quantum yields PHI-1 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.