The effect of two different UV absorbers combined with antioxidants on UV resistance of HDPE

In order to improve the aging resistance of HDPE, antioxidants (Irganox1010 and Irgafos168) are combined with UV absorber (UV-326 or UV-531). Analyses of ultraviolet–visible (UV–vis) and Fourier transform infrared spectroscopy show that UV-326 has a better capacity of UV absorbance, but easier to migrate to the HDPE surface due to the bigger difference of solubility parameter with HDPE than UV-531. The mechanical property indicates a better synergistic effect between UV-531 and antioxidants. With the single addition of antioxidant, the mechanical property sharply decreased to low level during irradiation for 200 h. With single addition of UV absorber, the elongation at break of the sample can still be maintained at about 700% until irradiation for 600 h. When two different UV absorbers are used in combination with antioxidants, HDPE with UV-326 maintains high mechanical property when irradiated for 1200 h, while the samples containing UV-531 still maintain good mechanical property when irradiated for 1600 h.