Aromatic poly(ether-urethanes): effect of the polyol molecular weight on the photochemical behaviour

Poly(ether-urethanes) based on 4,4'-methylene bis (4-phenylisocyanate) or t oluene diisocyanate and poly(tetramethylene oxide) have been synthesised va rying the molecular weight of the soft segment. The hard/soft segment mixin g has been studied by differential scanning calorimetry and Fourier transfo rm infrared spectroscopy. The polymers have been exposed to UV radiation, a nd the changes in the chemical structure have been analysed by FTir spectro scopy. The extent of the photodegradation in the urethane linkage increases with soft segment molecular weight. The phase separated structure is a cri tical factor which must be taken into account in order to study the photode gradation of the hard segments in poly(ether-urethanes). (C) 1999 Elsevier Science Ltd. All rights reserved.