thf after dissolution of the polymer in the thf 2 propanol was added to react with any isocyanate end groups and the solution was stirred for 1 hour the resulting polymer was isolated by evaporating the solvent under reduced pressure and characterized for identity ir molecular weight gpc and thermal properties dsc synthesis and characterization of two typical absorbable crystalline polyether ester urethanes c pu 1 and c pu 2 poly ester urethanes c pu 1 and c pu 2 were prepared using the method of example 1 the poly ethylene glycol used in c pu 1 and c pu 2 had a molecular weight of 1000 dalton for poly ester urethanes c pu 1 and c pu 2 0 025 and 0 025 moles of poly ethylene glycol 0 46 and 0 48 moles of 1 lactide 0 08 and 0 05 moles of glycolide 6 71 u00d7 10 u2212 5 and 6 64 u00d7 10 u2212 5 moles of tin ii 2 ethyl hexanoate and 0 017 and 0 017 moles of 1 6 diisocyanatohexane were used respectively polymers c pu 1 and c pu 2 were characterized for molecular weight by gpc using dichloromethane as the mobile phase which resulted in m n of 18 and 22 kda m w of 38 and 133 kda mp of 24 and 63 kda and pdi of 2 2 and 6 1 respectively six mg samples of c pu 1 and c pu 2 were annealed in 5 ml glass vials submerged in a 70 u00b0 c oil bath for 1 75.