Photo-crosslinking of polymers bearing p-(formylamino)-styrene units

Photosensitive polymers were synthesized by radical copolymerization of p-(formylamino)-styrene1 (1) with styrene (2), butyl methacrylate (3) or methyl methacrylate (4). On irradiation with 254 nm light the polymers become insoluble in solvents. Effects of the fraction of 1 units in the copolymers and of the polymers structure on the photoinduced insolubilization of the polymers were studied. The insoluble fraction of the exposed polymer films was enhanced by post-heating. The quantum yield of the photolysis of 1 units in polymers was almost independent of the polymer structure. From model reactions employing formanilide, a mechanism of insolubilization of the polymers was discussed.