Changes in appearance and chemical structure of chosen polymer materials under accelerated aging

Polymers, due to their versatility, have become indispensable in human life. In outdoor applications, all polymers degrade, resulting in a change in the properties of most polymers. Symptoms of polymer degradation include changes in esthetic appearance (e.g. discoloration, changes in gloss, chalking) and alteration of some specific polymer properties. In this study, polyamides 6 and 6.6 and polypropylene were subjected to UV irradiation and high temperature. The degradation was monitored using colour measurement and FTIR spectroscopy. The effect of deterioration in the material surface due to aging can be seen in its changes in colour (by altering its chemical structure), gloss and transparency. The colour measurement was performed in CIELAB system in tristimulus colour value L', a', b". FTIR spectroscopy measurements made it possible to show in a systematic way the changes in molecular structure of tested materials according to the process of aging, as well as possible mechanism of degradation.