Comparison of UV resistance of HDPE added with hindered amine light stabilizers with different molecular structures

UV resistance of versatile plastics has been received attention for a long time, especially of high-density polyethylene (HDPE). It was studied systematically that hindered amine light stabilizer (HALS) with different molecular structures had an effect on the UV resistance of HDPE. The molecular weights of the two HALS were 423.7 and 2100–3000 g/mol, respectively. It was found that the low-molecular-weight HALS outperforms the polymeric one of HDPE matrix in UV resistances due to the different molecular structures. HDPE-containing HALS with different molecular structures followed different degradation mechanisms during artificial accelerated aging. In addition, HDPE matrix composites with low-molecular-weight HALS show better mechanical properties than the polymeric one because of the decrease of delay of molecular chain fracture during irradiation. Therefore, HDPE matrix composites with low-molecular-weight HALS have better UV degradation resistance. However, polymeric HALS has the advantage of hard to move out of the sample surface.