Synthesis and characterization of segmented copoly(ether urea)s with uniform hard segments

Employing protective group strategy and novel isocyanate chemistry, segmented copoly(ether urea)s with uniform hard segments were prepared. Amine-terminated poly(tetrahydrofuran) served as the soft segment of these polymers. The size of the hard segments and the number of urea groups it contains were varied systematically, and their influence on the properties was investigated. The strength of hydrogen bonding between the urea groups in monodisperse hard segments containing exactly 1 to exactly 4 urea groups was studied by infrared spectroscopy and compared with materials containing polydisperse hard segments. The strength of hydrogen bonding in polymers possessing exactly two urea groups per hard segment resulted in an optimal balance between excellent mechanical properties and good processability and solubility.