Synthesis and Photoinitiating Activity Study of Polymeric Photoinitiators Bearing BP Moiety Based on Hyperbranched Poly(ester-amine) via Thiol-ene Click Reaction

A series of polymeric photoinitiators (BP-HPEAs) bearing BP moiety based on hyperbranched poly(ester-amine) were synthesized via the thiol-ene click reaction of 3-(4-benzoylphenoxy) propyl 2-mercaptoacetate (BPPM) with acrylated HPEA. BPPM was obtained by the esterification of (4-(3-hydroxypropoxy) phenyl) phenyl methanone (HPPM) with mercaptoacetic acid in the presence of p-toluene sulphonic acid as a catalyst. HPEA was prepared through Michael addition of piperazine with tri(hydroxymethyl) propane triacrylate. Their molecular structures were confirmed by the (1)H NMR, (13)C NMR, and FTIR analysis. The UV-vis spectrum analysis results showed that BP-HPEAs exhibit the stronger n-pi* absorption at similar to 340 nm with over two times higher molar extinction coefficients than BP at the concentration of 1.00 x 10 (3)M. The photoinitiating activity study showed that the maximum photopolymerization rates of 1,6-hexanediol diacrylate initiated by BP-HPEAs in the absence of coinitiator were obtained by two times higher than that by BP in the presence of triethylamine as a coinitiator. Moreover, the excellent miscibility of BP-HPEAs with the commercial bisphenol A epoxy diacrylate was achieved according to the T(s)/T(g) ratios of over 9.0 from DMTA. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1494-1501, 2012