Effect of Natural and Accelerated Aging on the Mechanical Performance of a Composite Based on Recycled Multilayer Carton

A composite elaborated from waste material was studied for its proposed use as a wood plastic composite. Multilayer food cartons and recycled high density polyethylene were used for the elaboration of laminates, in a proportion of 55 per cent and 45 per cent volume fraction, respectively. The samples were subjected to an aging in an accelerated weathering (AW)chamber for 0, 500, 1000 and 2000 h with UVB radiation, temperature and humidity cycles. Samples exposed to natural weathering (NW)for 0, 1300, 2600 and 5200 h, in a warm sub-humid environment were also studied, the aim being to elucidate a correlation of the useful lifespan of the material. In both cases, after the exposure, three-point bend tests were performed to evaluate the effect on the mechanical properties. The analysis of the degradation process was carried out by infrared spectroscopy, indicating that the AW and NW samples showed deterioration of the material in different proportions. By mean of thermal analysis, it was possible to associate the degradation with the appearance and/or growth of the endothermic peaks, showing a variation in the melting temperature as the time of exposure to AW and NW increased, resulting in a change in the crystallinity percentage. The modulus of rupture (MOR)and the flexural modulus of elasticity decreased by 20 per cent in samples subjected to AW for 2000 h; while in the samples exposed to NW, required of 5200 h to obtain a reduction of 16 per cent in the MOR.