SynopsisPhotocrosslinkable polymer is prepared from amorphous poly(methy1 vinyl ketone) (A-PMVK) obtained by anionic polymerization of methyl vinyl ketone. The reaction of A-PMVK with cinnamoyl chloride proceeds in pyridine a t 50°C. The photosensitivity of the polymer obtained is measured by infrared and Ultraviolet photometry. The polymer is of a crosslinkable type and forms cyclobutane linkage by ultraviolet irradiation. The polymer is coated on a lithographic aluminum plate and exposed t o arc and high-pressure mercury lamps. Development is with benzene, and standard inking by lithography is applied. The imaging area on the plate is stable and harder than poly(viny1 cinnamate), due t o intra-and intermolecular cyclization of the main chain. Many good reproductions are produced in the lithographic proofing machine. The photosensitive polymer obtained by A-PMVK is very useful in relief plates requiring etching.

SynopsisThe correlation between IR spectra and conformations was examined in alkyl vinyl ketone monomer. The stretching absorption bands of double bonds shift to lower wave number with the decrease in Taft's o* values of alkyl groups, and, conversely, the deformation band of the vinyl group shifts to the higher wave number. The inductive effect of the alkyl group is apparently three times larger in s-cis conformation than that in the s-trans. Absorption coefficients in the double-bond stretchings ( A C=O and A C=C) were measured in each conformation. Both conformations have a nearly equal value of A C=O. The ratio ( A s-cis/A s-trans) C=C is 3.4 f 1.0. The ratios (A' C=O/A' C=C) are 4.5 f 0.6 for the s-cis conformation and 15 f 2 for the s-trans conformation in all alkyl vinyl ketones studied.

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