Photopolymerization of urethane dimethacrylates synthesized via a non-isocyanate route

Urethane dimethacrylate monomers were synthesized via a non-isocyanate route from the reaction of a urethane diol with methacrylic anhydride. The urethane diols were synthesized through the reaction of ethylene carbonate with 1,6-hexanediamine, 3-amino-1-propanol and 2,2-dimethyl-1,3-propanediamine. H-1 NMR, C-13 NMR and FTIR spectroscopies confirmed the structure of the monomers. Elemental analysis confirmed the purity of the monomers. Photopolymerization of these multifunctional monomers was investigated with respect to polymerization rates and conversions using photoinitiated differential scanning calorimetry. Irgacure 651(R) was used as an initiator at 2 mol%. Photopolymerization results indicate high peak polymerization rates, 0.09 s(-1) compared to 0.06 s(-1) for bis-GMA and 0.07 s(-1) for HDDMA polymerized under the same conditions. Overall bulk conversions were 70-78%, compared to 68 and 76% for bis-GMA and HDDMA, respectively. The methodology developed here utilizes diamines and amino-alcohols that are members of commercially available families possessing a large range of structures, thus allowing synthetic flexibility in obtaining new urethane dimethacrylates with desirable properties. (C) 2003 Elsevier Ltd. All rights reserved.