Photochemical grafting of acrylated azo dyes onto polymeric surfaces. IV. Grafting of 4-(N-ethyl-N-2-acryloxyethyl)amino-4'-nitro-azobenzene onto cellulose

Photochemically induced grafting and graft-polymerization of 4-(N-ethyl-N-2-acryloxyethyl)amino-4'-nitro-azobenzene I, brought into contact in the solid state with cellulose by evaporation of solvent from monomer solutions, has been investigated kinetically at 30°C. Two constant rate periods were observed. The first one was interpreted on the basis of a self-sensitized grafting mechanism of monomeric or oligomeric species of I, photochemically initiated by hydrogen abstraction from the cellulose surface. The second one was explained as a self-sensitized photochemically induced graft-polymerization of I on the first grafted layer. Some particular features, such as concurrent photodegradation of the first grafted layer at low surface coverage, are discussed in the light of the proposed mechanism.