Synthesis and characterization of oligomers containing the α‐aminoalkylphenone chromophore as oligomeric photoinitiator

An oligomeric photoinitiator containing α‐aminoalkylphenone photoactive chromophore in the main chain was prepared from diphenyl ether, α‐chloroisobutyryl chloride, and piperazine through acylation, bromination, epoxidation, and polycondensation. The obtained oligomeric photoinitiator was characterized by GPC, TGA, traditional DSC, FTIR, NMR, UV–vis absorption, and fluorescence spectroscopy. The number‐average molecular weight (M_n) of the oligomeric photoinitiator was determined to be 2000–4000. The excitation and emission wavelengths of the fluorescence spectra were 376 and 473 nm, respectively. The thermal stability of the oligomer was found to be perfect with a decomposition temperature greater than 300°C. All the spectroscopic and thermal analyses clearly confirmed the consistence of property and structure. In a comparative photo‐DSC investigation, the oligomeric photoinitiator showed high photoinitiating efficiency while using 1,6‐hexanediol diacrylate as monomer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3417–3424, 2006