molar ratio of pop2000 to sma is more than 1 progress of the reaction is monitored with gpc and ir to confirm no cross linking between the synthesized comb like polymers the excess pop2000 is isolated with a solvent mixture of water or toluene and ethanol due to different solubilities of the comb like polymer and the straight chain polyoxyalkylene amine the unreacted pop2000 can be dissolved in the solvent mixture and pop2000 sma cooh precipitates repeat step b of example 1 but the stabilizer is replaced with pop2000 sma cooh jeffamine u00ae ed 2001 and m2070 are first dewatered in a vacuum oven at 100 u00b0 c for 6 hours and mdi is purified with decompressing distillation to a three necked bottle 100 ml the linker mdi 1 5 g 6 mmol previously dissolved in toluene 15 g is added and then ed 2001 5 99 g 3 mmol previously dissolved in toluene 10 g is added drop by drop the solution is continuously mixed with a magnetic stirrer next m2070 11 99 g 6 mmol previously dissolved in toluene 20 g is added into the solution the molar ratio of mdi ed 2001 m2070 is 2 1 2 the reactor is filled with nitrogen during the.