Synthesis and characterization of the non-isocyanate poly(carbonate-urethane)s obtained via polycondensation route

This paper presents a non-solvent and non-isocyanate synthetic route towards the linear aliphatic and aliphatic–aromatic poly(carbonate-urethane)s. As the polyurethane hard segment precursors, urethane diols were applied. These monomers were obtained in two steps. Firstly, the bis(methyl carbamate)s of appropriate diamine were prepared using dimethyl carbonate. Next, the urethane diols were obtained via transurethanization of alkylene or arylene bis(methyl carbamate)s with an excess of 1,5-pentanediol. As a polyurethane soft segment precursor, an amorphous oligo(hexamethylene-co-pentamethylene carbonate) diol was used. The influence of the polyurethane structure on mechanical and thermal properties of the obtained non-isocyanate poly(carbonate-urethane)s was studied. It was found that the presence of pentamethylene carbonate units facilitates removal of the low-molar-mass polycondensation products from the system and decreases the time of reaction needed to gain high-molar-mass polymers. The poly(carbonate-urethane)s were characterized by 1H NMR, 13C NMR, and FT-IR spectroscopies, MALDI-ToF spectrometry, DSC, TGA, GPC, and mechanical testing. The aliphatic poly(carbonate-urethane)s exhibited tensile strengths >40 MPa, while the aliphatic–aromatic ones showed tensile strengths up to 50 MPa. Poly(carbonate-urethane) possessing the 80 wt% of hard segments based on 1,4-diaminobutane displayed comparable mechanical properties to commercially available isocyanate-based poly(carbonate-urethane)s e.g. Bionate® PCU 80A and Carbothane® PC3575A.