Photochemistry of polymeric systems. IV. Photocrosslinking of copolymers including pyridinium dicyanomethylide groups

Photocrosslinkable polymers were obtained by reacting tetracyanoethylene oxide with pyridine units of suitable copolymer. Copolymers of styrene and 4‐;vinylpyridine dicyanomethylide were synthetized and studied. The methods used for characterization of photocrosslinked films were a “photoresist test” or the measurement of the insolubilization ratio. The reaction is favored by triplet‐;state sensitizers such as Michler's ketone. The photosensitivity of the copolymers was determined as a function of the wavelength of the radiation used.