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

Photooxidation of 4,4'-methylene bis(4-phenylisocyanate) and toluene diisoc yanate based poly(ester-urethanes) has been followed by means of Fourier tr ansform infrared spectroscopy as a function of soft segment molecular weigh t. The results have been related to the hard/soft segment phase mixing, stu died by differential scanning colorimetry. The extent of the photolysis reaction in the urethane linkage is more relev ant in higher soft segment molecular weight based polymers. The phase separ ated structure is a critical factor which must be taken into account in ord er to study the extent of the photodegradation of the hard segments in arom atic poly(ester-urethanes). (C) 2000 Elsevier Science Ltd. All rights reser ved.