The present work concerns the photodegradation of macromolecules having phenyl and carbonyl groups along the main chain. The photochemical behaviour of different polyketones is expected to give useful information about the mechanisms of the reaction. With this purpose we have considered polyketones constituted of 3-0x0-I,-1 diphenylbutane-1,4 diyl (I) units regularly head to tail linked, and polyketones of 3-0x0-1-2-diphenylbutane-l-4 diyl units (II and III). The synthesis of I by hydrolysis of polymers of 3 acetoxy-l,ldiphenylbutane-l-3 diene 2~ and II, III by hydrolysis of polymers of 3-acetoxy-1,2 (and 1,4)-diphenylbutane-1,3 (51, 8a) were successful. The tests of polymerization of trimethylsiloxy monomers have not been conclusive; the photochemical behaviour of these polyketones is in good agreement with the previously observed mechanism of degradation of polyketones having a phenyl or fi phenyl carbonyl groups. Rksumk-Ce travail conceme la photodkgradation de polymtres posddant des groupes phinyle et carbonyle le long de la chaine principale. Le comportement photochimique des diffirentes polyc&ones doit donner des renseignements sur les mtcanismes de photod6gradation. C'est pourquoi des poly&tones constituCes d'enchainements tbte-queue de motifs 3-0x0-l , l-diphknylbutane-1,4 diyle (I), 3-0x0-1,2diphknylbutane-1,4 diyle (II) et 3-oxo-l,Cdiph&nylbutane-I,4 diyle (III) ont tti pr.5par&s. La syntht5s.e de ces polyc&ones a Ct& tentke par hydrolyse des polymbres du 3-ac&oxy (4,4; 1,2 et 1,4) diphtnylbutane 1,3 dikne. Des essais de polymtrisation des monom&res portant des groupes trimbthylsiloxy n'ont pas Ctk concluants. Le comportement photochimique de ces polyc&ones est en bon accord avec les m&canismes pr&&demment observb pour la d&gradation des polytitones posddant un groupe phCny1 en a ou /I du carbonyle.