Synthesis and photoinitiating activity study of polymeric photoinitiators bearing BP moiety based on hyperbranched poly(ester‐amine) via thiol‐ene click reaction

Abstract

A series of polymeric photoinitiators (BPHPEAs) 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-p* absorption at $ 340 nm with over two times higher molar extinction coefficients than BP at the concentration of 1.00 Â 10 À3M. 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.

Thiol–ene “click” reactions and recent applications in polymer and materials synthesis: a first update

“…Interestingly, the polymeric species exhibited excellent absorption characteristics compared to benzophenone and was shown to have higher initiator efficiency in the subsequent polymerisation of HDDA. In a similar vein, Xie et al 33,34 reported two examples of benzophenone-based polymeric photoinitiators based on hyperbranched poly(ester-amine) and poly(ester/ ether) (P1000). In both instances the preparation of the polymeric photoinitiators involved a thiol-Michael reaction between appropriate functional species.…”

Progress in the development of polymeric and multifunctional photoinitiators

“…These two moieties were coupled via hydrosilylation of the hyperbranched organosilane (Scheme A red-shifted UV absorption in the HCPPI products was observed due to the introduction of alkyl. Xie et al [40] designed an A2B3 monomer system for the synthesis of hyperbranched polymer, which contains hydrogen donor for the Type-II PIs located on the terminal groups.…”

Difunctional monomeric and polymeric photoinitiators: Synthesis and photoinitiating behaviors

“…Therefore in recent years, polymerizable [5][6][7][8][9][10][11][12][13][14][15], oligomeric or polymeric photoinitiators (PPIs) [16][17][18][19][20][21][22][23] meeting most of the above mentioned requirements received continued interest due to their advantages in comparison with their corresponding low molecular weight non-monomeric analogs. The photoinitators derived from dendrimers and hyperbranched polymers were reported for their high functionality and low viscosity compared to linear polymers [24][25][26][27][28][29].…”