Elaboration of AA-BB and AB-type Non-Isocyanate Polyurethanes (NIPUs) using a cross metathesis polymerization between methyl carbamate and methyl carbonate groups

摘要

AA-BB and AB-type Non-Isocyanate Polyurethanes (NIPUs) were synthesized through a cross metathesis polymerization between methyl carbamate and methyl carbonate groups within AA-BB and AB monomers. These monomers were prepared by reaction of diamines, diols or amino-alcohols with an excess of dimethylcarbonate (DMC), using 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst. Due to a slight chain extension, dimethyl dicarbonate monomers as well as AB-type monomers contained few carbonate groups, which were present within the final NIPUs. The polymerization was performed in bulk at 200 degrees C, using K2CO3 as catalyst. Except for AB-type monomers obtained from amino-alcohols with 3 and 4 methylene groups, the polymerization was successful leading selectively to the expected NIPUs. These materials exhibited good thermal properties with Tg ranging from- 35 to 10 degrees C, T-m ranging from 96 to 256 degrees C and degradation temperature above 200 degrees C. The polyurethane properties were generally intermediate comparing to those of polyurea and polycarbonate analogues prepared in the same conditions.