Study On Design,Mechanism And Application Of Hydrogen Abstract System Based On Ketene Derivative For Led Photopolymerization

In the context of global environmental policies,developing photoinitiators with long wavelength absorption is a popular subject for traditional light source mercury lamp being toxic to creatures.With the"Minamata convention" coming into force,mercury lamp would be sifted out.Instead,LED lamp would be used as the main light source for photopolymerization.Limited by the bottleneck of LED technology,LED lamp with wavelength over 365 nm was available to be main light source for LED photopolymerization,which means those photoinitiators with short absorption wavelength would not meet LED lamp.Hence,developing photoinitiator matching LED lamp is urgent.In this research,we report furan and pyrrole ketene derivatives called BFC and BPC respectively could be used as type II photoinitiator for LED photopolymerization.In the presence of TEOA,initiating system BFC/TEOA and BPC/TEOA perform high efficiency for LED photopolymerization.The main contents are as follows:1.Although BFC shows excellent ability to absorb blue light,it initiated monomers with low efficiency upon LED irradiation.However,BFC could initiate monomers PEGDA with high efficiency.According to the research,we proved photo-isomerization produced by BFC could decrease BFC's initiating efficiency,while the complex effect formed by BFC and PEGDA could limit the photo-isomerization process and improved BFC's initiating efficiency.In the presence of PEGDA,initiating system of BFC/PEGDA exhibits high efficiently for other monomers.Moreover,BFC/PEGDA exhibits low biotoxicity and excellent photobleaching character.2.Based on the principle of the complex effect to inhibit the photo-isomerization of BFC to improve the initiating efficiency of BFC,TEOA which was proved to form charge transfer complex(CTC)and hydrogen bond complex(HBC)with BFC was investigated.Both the effect of CTC and HBC could limit the photo-isomerization of BFC and promised BFC's initiating efficiency.Photopolymerizaition kinetics proved initiating system BFC/TEOA performed higher efficiency than BFC/PEGDA.3.Pyrrole ketene derivative called BPC with less photo-isomerization was synthesized.In this research,we found E,Z-BPC formed by intramolecular reaction by itself exhibited low photo-active while hydrogen bond complex E,E-BPC-TEOA formed by intermolecular reaction with TEOA exhibited high efficiency during the LED photopolymerization.The initiating mechanism of E,Z-BPC and complex E,E-BPC-TEOA was discussed in depth via theoretical calculation.Moreover,the photobleaching character of BPC/TEOA and it's possible applications was proposed.4.Based on the interaction between BFC,BPC and TEOA respectively,initiating system BFC/TEOA and BPC/TEOA was proved to show excellent water solubility and could initiate the polymerization of waterborne monomer AM efficiently upon LED irradiation.In the result of TEOA consuming oxygen in the process of producing free radicals,both BFC/TEOA and BPC/TEOA showed oxygen inhibition resistance during the photopolymerization.5.A strategy to visualize both free radical and cationic photopolymerization's end point through BFC's luminescence characteristics was proposed.For BFC performing hydrogen transfer interaction with PEGDA,BFC's fluorescence intensity faded away in the free radical photopolymerization.Hence,free radical photopolymerization's end point could be evaluated by fluorescence quenching signal of BFC.For BFC exhibiting AIE character,BFC's fluorescence intensity got more and more bright as the viscosity of monomers increased in the cationic photopolymerization.Hence,cationic photopolymerization's end point could be evaluated by fluorescence enhanced signal of BFC.The strategy used for evaluating photopolymerization's end point could be potential for industry application.