Synthesis And Photoinitiation Activities Of Cationic Macrophotoinitiators

In this paper, two novel kinds of macro diaryliodonium salts were synthesized. They were (PSI) polystyrene-iodonium hexafluoroantimonate and (COPSI) poly -(styrene-iodonium-co-methylmethacrylate) hexafluoroantimonate and their photoinitiation activities were also researched, all these had offered the theoretical foundation for their applications.[hydroxy(tosyloxy)iodo]benzene was the most important intermediate in the reactions. I also compared two ways of synthesis of it. The yield was 85% by the method using per-acetic acid, and in this way I must first synthesized peracetic acid of high concentration. If using acetic anhydride, the yield would be lower, but the operation was simple. The synthesis reaction were studied and I got the optimum condition of the reaction through orthogonal experiment. When the molar ratio of polymer substrate and [hydroxy(tosyloxy)iodo]benzene was 5:1,reaction time was 24h(40℃) and the quantity of acetic acid as a catalyzer was 1mL, the obtained yield of macrophotoinitiator was the highest.The products were then characterized by 1H-NMR, FTIR, GPC, DSC, and UV-Vis spectrum, etc. The redshift phenomenon was observed in the ultraviolet spectrum . Because the phenyl iodonium groups were grafted to polymer chain, their ultraviolet spectra redshifted obviously, and their Tg also increased.After successfully synthesizing them, their photoinitiation activities in epoxy, epoxy acrylate, and complex systems were studied under 200W medium pressure mercury lamp, and the results showed that they had good photosensitivities, the post-curing abilities and excellent storage abilities. Their best concentrations were 3%wt or so. Their migration ratios in the cured film were much lower than the low-molecular photoinitiators.The reasons of the system volume shrinkage along with UV-curing were discussed. The problems of the volume shrinkage between the system of free radical curing and the mixture system of free radical/cationic curing were studied. Their applications in UV curing glass adhesives were studied. We found that the properties of the UV curing glass adhesives increased with the longer post curing time.In this article, two novel cationic macrophotoinitiators polystyrene-iodonium hexafluoroantimonate (PSI) was prepared by the reaction of polystyrene with [hydroxy(tosyloxy)iodo]benzene and poly(styrene-iodonium-co-methylmethacrylate) hexafluoroantimonate (COPSI) was prepared by the reaction of poly(styrene- methylmethacrylate) with [hydroxy(tosyloxy)iodo]benzene, which were not seen in other papers according to our knowledge. The resultant products could be expected to be primarily used for food, biomedical and drug packaging materials.