Accelerated Aging of Polymeric Composites Based on Waste with TiO2 Fillers

This study aimed to investigate the properties of composites based on polymeric waste with organic and inorganic fillers before and after accelerated aging for indoor or outdoor applications. The composites were obtained by compression molding from waste: tire rubber as a matrix, polyethene terephthalate (PET), and high-density polyethylene (HDPE) as organic fillers and TiO2 nanoparticles as inorganic fillers. The critical issue in ensuring good mechanical properties is the interface between the components of the composites. The effects of moisture, temperature, UV radiation, and salt fog on the mechanical properties of composites were evaluated. The modifications at the structural and molecular levels were evidenced by changes in FTIR, XRD spectra, contact angle measurements, and AFM analysis. To evaluate the durability performance of waste composites in this study, before and after accelerated aging samples were tested. The mechanical properties of the polymer composites with organic/inorganic filler materials depend on the interface between the organic-organic phase and/or the organic-inorganic phase, the processing temperature, and the characteristics of accelerated aging. Thus, the salt fog absorbed by the composite materials leads to a significant decrease in the values of the elasticity modules; the values of elongation at the break of the samples improve significantly with the decrease in the temperature of maintaining the samples; and the interactions between the polymer and the inorganic filler materials have the effect of increasing the energy of molecular cohesion and, implicitly, the thermal energy required to activate the thermal degradation mechanism.