ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Photolysis of Carbonyl Polymers in Solution

I. Lukáč, I. Zvara, P. Hrdlovič, and Z. Maňásek

Institute of Polymers, Slovak Academy of Sciences, Bratislava 9

Abstract:  The photolysis of poly (vinyl phenyl ketone) (PVPK), poly (vinyl methyl ketone) (PVMK), poly(isopropenyl methyl ketone) (PIMK) and copolymers of vinyl phenyl ketone with methyl methacrylate (VPK/MMA) and with styrene (VPK/S) at 313 nm in methylene chloride solution has been studied viscometrically. The dependences of the main chain scission on time were linear which indicates random scission. Stern —Volmer dependences of t h e ratio of the quantum yield of the main chain scission without and with the quencher (2,5-dimethyl-2,4-hexadiene) vs. quencher concentration have been linear in the studied concentration range for all polymers investigated except for PVMK. The quenching constants decrease in the following sequence: VPK/MMA, VPK/S, PVPK, PVMK, and PIMK, respectively. The lifetime of t h e first triplet state of the polymers decreases in the same way. Both the photodegradation rates and the quenching constants for the copolymer VPK/MMA have been measured in various solvents of different viscosity. The photodegradation rate and the quenching constant decrease with increasing solvent viscosity (microviscosity) which indicates the diffusion-controlled transfer of triplet energy from polymer donor to low-molecular acceptor. Lower photodegradation rates and quenching constants with regard to the appropriate viscosity have been observed in the chlorinated aliphatic hydrocarbons. The quenching properties of different compounds have been followed at VPK/MMA photolysis in chlorobenzene solution.

Full paper in Portable Document Format: 265a404.pdf

Chemical Papers 26 (5) 404–411 (1972)