Unexpected Synthesis of Segmented Poly(hydroxyurea–urethane)s from Dicyclic Carbonates and Diamines by Organocatalysis

• DOI: 10.1021/acs.macromol.8b00731
• Publication Date: 2018-07-18T22:12:49Z
• Authors: Amaury Bossion; Roberto H. Aguirr...; Lourdes Irusta; Daniel Taton; Henri Cramail; Etienne Grau; David Mecerreyes; Cui Su; Guoming Liu; Alejandro J. Müller; Haritz Sardon
• Keywords: Isocyanate; Polyurea; Step-growth polymerization

A complete study of the effect different organocatalysts on step-growth polyaddition a five-membered dicyclic carbonate, namely diglycerol dicarbonate, with poly(ethylene glycol)-based diamine in bulk at 120 °C was first carried out. The reaction found to be dramatically catalyst-dependent, higher rates being observed presence strong bases, such as phosphazenes (t-Bu-P4 or P4) and 5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). Unexpectedly, as-formed urethane linkages entirely vanished time, evidenced by FTIR 13C NMR spectroscopies, while signals due urea bond formation progressively appeared. An advantage chemical transformation occurring from further taken optimizing polymerization conditions access range poly(hydroxyurea–urethane)s (PHUUs) precise ratio one-pot process. Characterization corresponding polymers rheological measurements showed that storage modulus reached plateau high temperatures contents. application temperature could thus increased 30 140 °C, for regular polyurethanes. Furthermore, SAXS phase-contrast microscopy images demonstrated increasing content improved phase separation between soft hard segments these PHUUs. Altogether, this novel, straightforward, efficient, environmentally friendly strategy enables non-isocyanate poly(urea–urethane)s tunable urethane-to-urea carbonates following an organocatalytic pathway.