Segmented copolyetherurethane‐ureas and semicarbazides for blood circulation systems, III. Mass spectrometric investigations 1, pyro‐field ion mass spectrometry

The pyro‐field ion mass spectra of urea or semicarbazide linked copolyetherurethanes have been measured with a maximum pyrolysis temperature of 873 K. The polyethers with hydroxy endgroups [poly(oxyethylene), poly(oxytetramethylene), poly(oxypropylene)] and the diisocyanates [4,4′‐diisocyanatodicyclohexylmethane, 4,4′‐diisocyanatodiphenylmethane, 2,4‐diisocyanatotoluene] used for the synthesis can be identified from the spectra without difficulty. Among the diamines [ethylenediamine, hexamethylenediamine, 4,4′‐diaminodiphenylmethane, 1,3‐bis(aminomethyl)benzene] and isophthalic acid dihydrazide used for the coupling of the prepolymers bearing isocyanate endgroups, the aromatic diamines can easily be identified. Aliphatic diamines and isophthalic acid dihydrazide as structural units cannot be identified with the same reliability. Possible pyrolysis fragments suitable for the rapid and unambiguous identification of the building units of the polymer chains (“key fragments”) are given.