Synthesis And Property Study Of A New Type Of Acrylic Macrophotoinitiators

UV-curing technology is a new type of green curing technology. Ptotoinitiator is a very important part of curing system, is the key factor that UV-curing becoming a new way of curing, and determine the curing speed and curing degree of curing system, relate to the success or failure of the whole curing process. However the polymerization products by traditional small molecule photoinitiator are more likely to have small molecular initiator residues, in the process of using, it is easily to volatilize and migrat and lead to product become yellow, have a smell, and even produce toxicity. Not only reduces the light efficiency but also has an impact on product quality and safety. Therefore, developing the polymerizable photoinitiators or macrophotoinitiators is an effective way to solve the drawback of the small molecule initiator.Irgacure2959(2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone) is a commercially available CIBA photoinitiator, with active hydroxyl in the structure.In this article, through the esterification reaction between crylic acid and Irgacure2959, the polymerizable photoinitiator monomer2959-AA was prepared. Polymerisation of HDDA (1,6-hexanediol diacrylate) was initiated using Irgacure2959and2959-AA to be polymerised was studied with a photo-DSC test. Results showed that2959-AA had higher chemical reactivity than Irgacure2959.Through the copolymerisation of acrylic monomers and2959-AA, two series of MPIs with different2959-AA contents and different glass transition temperatures were obtained. HDDA was initiated by the two series of macrophotoinitiators to be polymerised were studied with photo-DSC test. It was evident from the experiments that2959-AA content and molecular chain flexibilityin in the macrophotoinitiators progressively increased the polymerization rate and monomer conversion.Introducing hydroxyl with HEMA (hydroxyl ethyl methacrylate) in macrophotoinitiator and then a series of unsaturated macrophotoinitiators with different content of double bond were obtained throutgh the reactions between TMI (3-isopropenyl-2,2-dimethyl-benyl-isocyanate) and macrophotoinitiator. The photopolymerization behaviors of HDDA were initiated using unsaturated macrophotoinitiators to be polymerised were studied with photo-DSC test and the properties of UV-cured film were studied by DMA. Results showed that all initiators had good performance in photopolymerization and with the increase of the double bonds contents in unsaturated macrophotoinitiators the glass transition temperature and storage modulus of the films were increased, which indicated that unsaturated macrophotoinitiators have certain effect of crosslinking in curing system.