Preparation and characterization of novel UV-curable urethane methacrylatedifunctional monomers and their structure-property relationships, 1

Full Paper: Four new UV-curable cross-linking agents namely 2,2-bis(4-beta -ethoxy urethane ethyl methacrylate phenyl)propane (HEPIEM), 2,2-bis(4-beta -ethoxy urethane ethyl methacrylate phenyl)6Fpropane (HEPFAIEM), 2,2- (4-b eta -ethoxy urethane ethyl methacrylate-3,5-dibromo phenyl)propane (TBHEPAI EM), and 5-tert-butyl-1,3-bis(4-ethoxy urethane methacrylate phenyl)benzoyl benzene (tBuHEPBIEM), which can be good candidates for UV-curable coating a pplications, were synthesized by isocyanato ethyl methacrylate (IEM) with f our nt diets, The structures of the monomers thus prepared were characteriz ed by FTIR, mass and H-1 NMR spectroscopies. Introduction of new difunction al cross-linking agents affected the mechanical and physical properties of UV-cured films. Addition of 10% cross-linking agents into the formulations caused an increase both in tensile strength and elongation, when compared w ith widely used di(ethylene glycol)diacrylate (DEGDA) containing films. Elo ngation values of TBHEPAIEM containing films were exceptions. Gel contents of the UV-cured polymeric films were found to be between 88-98%. Thermograv imetric analysis showed that there were not any noticeable changes in therm al oxidative stability of the films compared with DEGDA containing ones. On the other hand, HEPFAIEM and TBHEPAIEM containing films showed increases i n char yields due to the presence of F and Br in their structures. Introduc tion of the new difunctional monomers lowered the water absorption values o f the films somewhat proportional to the methyl group content of the x-link ers.