Hydrophilic segmented polyurethane was prepared from hydroxyl terminated poly (ethylene oxide)-poly(tetramethylene oxide)-poly(ethylene oxide) triblock copolymer (HT-ETE), 4, 4'-diphenylmethane diisocyanate (MDI) and ethylene glycol (EG). HT-ETE consists of poly (tetramethylene oxide) (PTMO) segment of molar mass 2000 at the center and poly(ethylene oxide) (PEO) segment of molar mass 1020 at both ends. The hard segment content of the polyurethane is 18wt%. The polyurethane elastomer showed low modulus up to ca. 600% elongation. Tensile strength at break (TB) of dry film was ca. 13MPa, and that of wet film with water content of 98% went up to ca. 5MPa. The introduction of PEO to the end of PTMO brought about the characteristic morphology, i.e., the microphase separation was clearly observed and the distance of hard segment domains was smaller than that of segmented polyurethanes prepared from PTMO, MDI and EG. This morphology, together with the length of soft segment and the properties of hard segment domain, was considered to make the mechanical properties of the hydrophilic polyurethane closer to a soft tissue.
