Formation of aldehyde groups during the photolysis of poly(methyl methacrylate)

Abstract Upon u.v. irradiation at λ inc = 253.7 nm poly(alkyl acrylates) and poly(alkyl methacrylates) form a new absorption band around 280 nm. This band is assigned at least partly to aldehyde groups attached to the main-chain. Aldehyde groups formed upon irradiation of poly(methyl methacrylate) were converted to 2,4-dinitrophenylhydrazone groups and detected by absorption spectroscopy performed in conjunction with gel permeation chromatography. Quantum yields of carbonyl groups capable of reacting with 2,4-dinitrophenylhydrazine were determined: φ (CO) = 4.4 × 10 −4 (argon) and φ (CO) = 8.0 × 10 −4 (air).