Photogeneration of polymeric amines: Synthesis, photocrosslinking and photoimaging of copolymers containing photoactive carbamate pendant groups

Two families of copolymers containing 4-[(2-nitrobenzyloxy)carbamoyl]styrene as the photoactive component, with styrene or methyl methacrylate as the other component are described. The polymers are prepared by chemical modification of copolymers of 4-aminostyrene with styrene and methyl methacrylate, respectively, using 2-nitrobenzyl chloroformate. The photoactive carbamate groups of both copolymers can be removed by irradiation with UV light below 320 nm. Quantum-yield measurements and comparisons with small-molecule model compounds confirm that attachment to the polymer has no effect on the photolability of the 2-nitrobenzylcarbamoyl protecting group. Quantum-yield values near 0.10 also compare favourably with those obtained for related small molecules. The photoactive polymers have been tested successfully in the UV-induced crosslinking of formulations containing epoxy groups.