Synthesis of Polyurea via the Addition of Carbon Dioxide to a Diamine Catalyzed by Organic and Inorganic Bases

The synthesis of polyurea via the addition of carbon dioxide (CO 2 ) to a diamine of 4,7,10-trioxa-1,13-tridecanediamine (TOTDDA) was investigated by using organic and inorganic base catalysts. It was found that 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was the most active among the catalysts examined. The influence of CO 2 pressure, temperature, and reaction time was examined for the DBU-catalyzed polyurea synthesis. The reaction mixture was analyzed by in situ high-pressure attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) under reaction conditions, and possible reaction mechanisms, in which DBU can activate both CO 2 and TOTDDA, were proposed. Physicochemical properties of polyurea materials synthesized were examined by several techniques. In addition, the catalytic performance of DBU was further examined for the addition of CO 2 to other different diamine compounds.