Application of antioxidant and ultraviolet absorber into HDPE: Enhanced resistance to UV irradiation

Herein, high density polyethylene (HDPE) matrix was applied as the polymer matrix for its excellent overall performance and low price. In the study, antioxidants (0.5 phr) and ultraviolet absorber (100 phr) were added into the polymer matrix (100 phr) to investigate their influence on UV resistance, respectively. The macroscopic properties and microstructure changes of the samples were both investigated through the characterizations of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), mechanical properties and thermogravimetric analysis (TGA). This work also conceived the three methods of capturing free radicals generated by photoaging, decomposing peroxides generated by photoaging, and absorbing ultraviolet light to achieve anti-aging effects. The results showed that the UV absorber improves the UV resistance of the material better than the antioxidant. After irradiation for 600 h under the aging condition of 0.51 w/m(2)@lambda = 340 nm, the samples added with UV absorber also still maintain their mechanical properties at a high level. For comparison, the samples added with antioxidants presents poor mechanical properties only after irradiation for 200 h. Besides, the crystallinity of HDPE and HDPE added with antioxidant significantly increased after irradiation, but the crystallinity of HDPE introduced with UV absorber presents slight changes before and after irradiation. Meanwhile, all the irradiated samples also maintained the original excellent thermal stability. According to the obtained results, the aging mechanism was also analyzed.