Non-Isocyanate Polyurethane Segmented Copolymers from Bis-Carbonylimidazolides.

Bis-carbonylimidazolide (BCI) functionalization enabled an efficient synthetic strategy to generate high molecular weight segmented non-isocyanate polyurethanes (NIPUs). Melt phase polymerization of ED-2003 Jeffamine ® , 4,4'-methylenebis(cyclohexylamine), and a BCI monomer that mimics a 1,4-butanediol chain extender enabled polyether NIPUs that contain varying concentrations of hard segments ranging from 40 to 80 wt. %. Dynamic mechanical analysis and differential scanning calorimetry revealed thermal transitions for soft, hard, and mixed phases. Hard segment incorporations between 40 and 60 wt. % displayed up to three distinct phases pertaining to the poly(ethylene glycol) (PEG) soft segment T g , melting transition, and hard segment T g , while higher hard segment concentrations prohibited soft segment crystallization, presumably due to restricted molecular mobility from the hard segment. Atomic force microscopy (AFM) allowed for visualization and size determination of nanophase-separated regimes, revealing a nanoscale rod-like assembly of HS. Small-angle x-ray scattering confirmed nanophase separation within the NIPU, characterizing both nanoscale amorphous domains and varying degrees of crystallinity. These NIPUs, which were synthesized with BCI monomers, displayed expected phase separation that is comparable to isocyanate-derived analogues. This work demonstrates nanophase separation in BCI-derived NIPUs and the feasibility of this non-isocyanate synthetic pathway for the preparation of segmented PU copolymers. This article is protected by copyright. All rights reserved.