Additives for ultraviolet-induced oxidative degradation of low-density polyethylene

ABSTRACT Polyethylene (PE) is one of the most widely produced and widely used plastics in the world. Saturated hydrocarbons cannot absorb the energy of the light reaching earth, so the degradation process is rather slow; this, in return, causes disposal problems. On the other hand, it was observed that in the presence of oxygen and impurities in the polymer matrix, the degradation could be reduced to shorter time intervals. In this study, vanadium(III) acetyl acetonate (VAc), serpentine (SE), and Cloisite 30B (CL) were used as additives, both together and alone, and we followed the photodegradation of PE. The amount of VAc was kept constant at 0.2 wt %, whereas the amounts of SE and CL were varied between 1 and 4 wt %. The samples were irradiated by UV light for up to 500 h. Mechanical and spectroscopic measurements were carried out during certain time intervals to monitor the degradation. VAc containing PE showed the fastest degradation. The elongation at break values of these samples were reduced to half of the initial value of elongation at break within five days. Combinations of the CL and SE additives were also proven to accelerate the degradation of PE; this was followed by an increase in the carbonyl index, which was observed to be at least 10 times greater than that of pure PE. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43354.