Radiation induced effects in segmented poly(siloxaneurethaneureas) based on aliphatic and aromatic diisocyanates

Poly(siloxaneurethaneureas) (PSURURs) prepared from aromatic and aliphatic isocyanates were investigated upon exposure to ionising radiation. Radicals are formed both in siloxane and urethane segments. In comparison with aliphatic analogues it was found that in aromatic PSURURs: (1) concentration of all radicals is lower, (2) relative concentration of methylene radicals formed in siloxane units is higher, (3) the radiation yield of H2 is more than three times smaller and (4) it seems that efficiency of cross-linking is less significant.