•Synthesis of a low molecular weight PS incorporating a photostabilizer additive.•The synthesized copolymer was used as a macroadditive in films of PS, HIPS and ABS.•The macroadditive did not cause significant changes in mechanical properties.•A mitigation of UV accelerated degradation process was observed for PS and ABS films.•The macroadditive offers a promising alternative to conventional stabilizers. Photostabilizer additives are employed to shield polymer materials from ultraviolet (UV) degradation. One category of such additives includes ultraviolet light absorbers (UVA), which absorb radiation and dissipate it within the polymer network as heat. These additives are typically incorporated into the polymer during processing, but they can pose challenges such as low miscibility and migration of the additive to the polymer's surface. A viable solution to these issues is the synthesis of polymers with additives chemically connected to the polymer chain. This work investigates the copolymerization of styrene with the additive 2-3-(2H-benzotriazol-2-yl)-4-hydroxyphenylethyl methacrylate (BHEM), resulting in the formation of PS-BHEM. This copolymer was then utilized in commercial polymers (PS, HIPS, and ABS) to mitigate degradation, with a comparative analysis of its effectiveness against the commercial stabilizer Tinuvin P. The copolymerization process yields a 92 % product, and the presence of BHEM is confirmed through SEC analysis. Accelerated weather degradation tests indicate that the incorporation of PS-BHEM enhances the UV stabilization of commercial ABS without altering the mechanical properties of the polymers.