Abstract
The structural changes after ageing of polyurethane by UV irradiation has been studied by comparative spectroscopic measurements. The polyurethane was prepared from diphenylmethane-4,4'-diisocyanate, (MDI) and polyester from adipic acid and ethylene glycol. The experimental results show that various oxidized structures are formed in UV degraded samples with simultaneous decomposition of polyurethane. This leads to the forma tion of new structures such as carbonyl, azo, carbodiimide, quinoid as well as polyene sequences. According to the experimental results and the data taken from the literature, the mechanism of the process was discussed.