Improvement of bis-GMA-based resins by urethane linkages: DTA and DSC thermal properties

Experimental bis-GMA/TEGDMA/urethane resins were investigated using synthesized urethane monomers to improve thermal properties. DTA (differential thermal analysis) results show that curing temperatures were 160 and 165°C in bis-GMA-based resins containing the synthetic 2 HEMA/N 3500 urethane monomer, 150°C in the resin containing the 2 HEMA/HT urethane monomer, and 153°C in the urethane monomer derived from 2 HEMA/N 3500. Also, DSC (differential scanning calorimetry) results show that the value of activation for polymerization during heating is lower in bis-GMA/TEGDMA containing synthesized urethane monomer (1.89, 2.44, 2.50 kcal/mol) than undiluted urethane monomer (7.50 kcal/mol) when these synthesized urethane monomers were diluted with bis-GMA/TEGDMA. With the use of urethane monomer as an additive to bis-GMA/TEGDMA it is possible to cure more rapidly with lower activation energy.