We have investigated the synthetic methods of segmented polyether polyurethane (PEU) through polytetramethylene glycol-4

4'-diphenyhnethane diisocyanate (PTMG-MDI) prepolymer with ethylene diamine (ED) as extender and observed that different methods of adding reagents in the two-stops solution polymerization -will result in the formation of two-phase components block copolymers with different morphology and somewhat different physical properties. Method A

adding PTMG solution to MDI then adding extender to the resulted prepolymer solution will always show better phase separation and give cystal herd domain in the size of 50--80A

while method Busual-ly give amorphous hard domain with much larger size of 1000--2000 A.