Long-term accelerated weathering of HAS stabilized PE and PP plaques: Compliance of ESRI, IR, and microhardness data characterizing heterogeneity of photooxidation

Polymers in various applications are subjected to photooxidation processes resulting in loss of their material properties due to appearance of oxidation products and consequent degradation. Heterogeneous space distribution of concentration of oxidation products, crystallinity, stabilizer concentration and microhardness (MH) can be determined utilizing IR microspectroscopy and microhardness tester, respectively. We devoted this paper to direct determination of heterogeneity of the above mentioned parameters inside PE polymer plaques stabilized with secondary HAS Tinuvin® 770 and to the comparison of the data with nitroxide concentration profiles determined by ESRI that outline heterogeneity of the oxidation process inside the plaques. Data on heterogeneity of photooxidation processes in PP plaques stabilized with Tinuvin® 770 or binitroxide Prostab® 5415 are presented for comparison.