Effect of Weathering on Tensile Properties of Low and High Density Polyethylene

This paper study the effect of weathering (humidity and ultra-violent) on tensile strength of low-density polyethylene (LDPE) and high-density polyethylene (HDPE). LDPE and HDPE were prepared using an injection machine process at temperatures (170-190°C), and the rotating speed of the injection screw is 50 rpm. The samples were exposed to moisture and ultraviolet (UV) environment. The UV samples were exposed to different exposure times (0-60-90-120 hours) using a UV lamp device. The moisture samples are exposed to humidity effect for (0-500-1000 hours) by using accelerated weathering devices. The mechanical behavior of the accelerated weathering samples, such as tensile strength and the modulus of elasticity, were investigated. The mechanical behavior of accelerated weathering samples shows that the tensile strength increased with increasing LDPE and HDPE exposure. However, an apparent drop decreased with increasing time exposure. Also, in the humidity exposure, the modulus and strength firstly increased with time exposure then decreased with increasing the exposure time for LDPE and HDPE.