Role of Ultraviolet Absorbers (UVA) and Hindered Amine Light Stabilizers (HALS) in ABS Stabilization

Abstract

The present work evaluates the combination effect of hindered amine light stabilizers (HALS) and ultraviolet absorbers (UVA) on the ultraviolet (UV) stability of acrylonitrile-butadiene-styrene (ABS). Thus, two types of light stabilizers, Tinuvin P and Chimassorb 119 FL, were used to improve the ABS endurance against UV. Stabilized ABS samples were submitted to accelerated weathering in a Xenontest 150 S chamber, according to standard methods, in order to predict copolymer lifetime within a commercially acceptable time period. Infrared spectroscopy with attenuated total reflectance accessory (FTIR-ATR) was used to follow chemical modifications that occur on the material surface as a consequence of degradation process. While non-stabilized ABS samples loose the butadiene component in the first 22 h of exposure, in stabilized samples submitted to same accelerated conditions this component only disappears after 150 h of exposure. Non-stabilized and stabilized ABS samples present a similar yellowing behavior, a gradually increase with exposure time. Nevertheless, as expected, color modifications are less pronounced for stabilized ABS samples. The results obtained suggest that a better performance was achieved for stabilized ABS samples with Tinuvin P and Chimassorb 119 FL, which is very important to extend the copolymer lifetime.

Color changes due to thermal ageing and artificial weathering of pigmented and textured ABS

“…The strongest effect was noticed with the WoM‐treatment; after 600 h in the test chamber, the b*‐ value had increased about 40%. This is in agreement with the results reported by Santos et al [20] who observed an increase in the yellowness index after exposure to UV‐ light.…”

“…FTIR is an important tool for characterizing degradation of polymers and consequently it has been applied to ABS in several studies [2, 3, 20, 24]. Here only changes induced by the ageing to the absorption bands corresponding to carbonyl groups (1600–1800 cm −1 ), 1,4 butadiene (966 cm −1 ) and 1,2 butadiene (911 cm −1 ) will be discussed.…”

Effects of solar UV and climate change on materials

“…74, 75 Blending light stabilizers (UV absorbers with HALS) to obtain synergistic effects is of considerable research interest. 76 Polyesterpolyurethane clear-coat formulations that contained both HALS and UV absorbers, for instance, show a synergistic light-stabilizing effect. However, this is not a general observation.…”