Different molecular structure of pigments versus traditional UV Stabilizers on the UV irradiation life of HDPE

As the demands on high-density polyethylene for weather resistance, aesthetics and functionality continue to improve, copper phthalocyanine has recently received attention for enhancing the weathering properties of high-density polyethylene. However, little research has been done on other pigments whether to improve weathering resistance equally. In this work, inorganic and organic pigments added to matrix were explored and compared with the industrialized UV stabilizers. It was found that pigmented polyethylene showed very little color change during 2000 h irradiation except for polyethylene/ultramarine. After 2000 h irradiation, polyethylene/copper phthalocyanine was the best among pigmented polyethylene in tensile strength, copper polychlorinated phthalocyanine following. These two pigments were similar to commonly used light stabilizers in their ability to stop the aging of polyethylene. Chrome oxide and ultramarine were worse, basically aging after irradiation of 500 h. This was consistent with the order of UV absorption ability of pigments at 310 nm - 400 nm.