The accelerated aging impact on polyurea spray-coated composites filled with basalt fibers, basalt powder, and halloysite nanoclay

Abstract

In this study, the resistance to accelerated aging of composites with a matrix of two-component aromatic polyurea (PUA) reinforced with inorganic fillers was assessed. Polyurea composites with various contents of 5–20 wt% of three types of fillers, i.e., basalt powder (BP), basalt milled fibers (BMF), and halloysite nanoclay (HNC), produced in the spray-forming process, were subjected to laboratory simulated accelerated aging with exposure on UV light for 100 h. Samples with different exposure times to UV light radiation were subjected to qualitative and quantitative analysis to determine differences in structural changes of unmodified polyurea and its composites. Coupled spectroscopic measurements (FTIR, UV–Vis, and color evaluation) were analyzed concerning changes in the samples' surface structure, assessed by the SEM method coupled with EDS, and changes in mechanical properties carried out in the static tensile test. The research showed the simultaneous occurrence of degradation phenomena resulting from photooxidation and photodegradation. The analyses proved that the oxidation and mechanical damage depths, resulting from the photooxidation and the crazing caused by the degraded surface layer phenomena' brittleness, were approx. 25 μm and 50 μm respectively. It was shown that composite samples subjected to accelerated aging, despite a significant deterioration of the spray-formed products surface quality, reveal an improvement in their mechanical properties.