The Study Of Novel And High Performance Photoinitiator

Photo-curing technology possesses the high curing efficiency,environmental protection,solvent-free and energy saving compared with traditional curing.It has many applications in photoresist,adhesive,surface pattern,electronic packaging materials,3D printing and dental restoration materials.But as the industry upgrades and frontier science develops,the higher efficient,more soluble photoinitiator is desired.Water-soluble photoinitiators is also a hot topic due to its advantages in environmentally friendly production.Photoinitiator that has good absorption wavelength and well-soluble in water is still in urgent need of development.Based on these problems,we synthesized four quioxaline photoinitiators combining with thioether bond(SQ).Among them,SQ2 possesses a visible absorption and all of them have good photochemical activity.Photo-cleavage and ESR experiements showed SQ had cleavable and hydrogen-abstracting groups at the same time.We confirmed its photocleavage mechanism with HPLC/MS and found the cleavage products.Photopolymerization of HDDA was operated with SQ and no hydrogen donor was added,the double bond conversion could be reached to 80%.Upon the addition of EDB,the conversion of HDDA could be improved to almost 100%.These showed the good initiation performance.Finally,we tested its efficiency in multi-functional monomers and got 100% double bond conversion.For the demand of aqueous photopolymerization,we also developed the aqueous photoinitiation system.Hyperbranched polyether amine acts as the micelle host after self-assembly in water and photoinitiator acts as the guest.Many active groups with hydrogen atom could serve as hydrogen donors,the excited state guest internal could abstract hydrogen from these groups and generate radicals.The photodegradation experiment of Nile Red and camphorquinone verified the suppose.DLS tests indicated the guest monomer had great influence on the parameter of micelles.The high concentration active groups and photoinitiators could generate radicals quickly.ESR spectrum also possessed a high intensity,which means the large number of radicals.The different proportion of hydrophobic chain had different loading efficiency on photoinitiator.The increased hydrophobic chain may contribute to the increase of micelle size but may be disadvantageous for loading efficiency.hPEA211 is the best choice and the average loading rate of micelles could be reached to 15%.Photopolymerization of AM and PEGDA-700 initiated by hPEA211/PI under 365 nm showed the excellent double bond conversion compared with normal water-soluble photoinitiator,I2959.Almost all of them could reach 100% conversion.However,due to the viscosity of the solution had influence on self-assembly of hPEA211,some PIs like HABI may escape from the cage of micelles and reunited together.That may decrease the photoactivity of photoinitiation system.Finally,photopolymerization of PEGDA with a series of concentrations of hPEA211/CQ was operated under 450 nm and got the 100% double bond conversion.