Influence of the testing conditions on the efficiency and durability of stabilizers against ABS photo-oxidation

Abstract

Exploitation of knowledge of the efficiency of stabilizers on acrylonitrile-butadiene- styrene stability is very important for appropriate selection of stabilized systems. With the aim of studying the influence of testing conditions on the effectiveness of stabilizers, several compositions were prepared by extrusion and submitted to different weathering conditions. UV/Vis spectroscopy and high performance liquid chromatography were used to assess the durability of stabilizers during the exposure time. Different behaviour was found under natural and accelerated weathering. Although all stabilizers induced a decrease of ABS degradation rate during accelerated weathering, the best results were achieved when combinations of light stabilizers with phenolic antioxidants and trivalent organo phosphorus compounds were used. Natural exposure enhances the degradation process when compared to data obtained in an accelerated chamber under similar light source characteristics. This behaviour suggests that there are other atmospheric parameters that play an important role in the degradation process. The results also showed that a combination of stabilizers and antioxidants induces a decrease of the oxidation rate in the initial stage of degradation under natural weath- ering conditions. Nevertheless, this synergetic effect is limited for the degradation time studied.