CHEMICAL EFFECT ON ROTATIONAL MOLDING GRADE CROSS-LINKED HIGH DENSITY POLYETHYLENE (XLHDPE) WITH VARYING CONCENTRATION OF ANTIOXIDANT AND UV STABILIZER

Chemicals effect from the environment and liquid chemicals (diesel and petrol) on rotational molding grade (HD3840UA) high density polyethylene (HDPE) and cross-linked HDPE samples were studied according to ASTM D1435 and ISO 175: 1999. The HDPE (pure) and cross-linked HDPE samples with various antioxidant concentrations (0.0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%) were prepared. Samples were immersed in the liquid chemicals at 23oC for the immersion test. The weathering test was conducted to study the effected of chemical in the environment by exposing the samples to the natural atmosphere. The duration of the test is 1 day, 1 week and 8 weeks. Tensile test was carried out according to ASTM D638-02 to determine the stress at break, elongation at break and Young’s Modulus. The changes in weight and dimension were also determined. The tensile properties result show that the rate of degradation for the petrol immersion is more than diesel immersion at 23oC for both HDPE and cross-linked HDPE samples. Both samples experienced apparent reduction in the tensile properties within 24 hours, regardless of antioxidant concentrations. Physically the sample immersed in diesel shows a higher swelling ratio. The HDPE is more susceptible to liquid chemical as well as atmospheric attack. The cross-linked HDPE with optimum level of antioxidant contents is the most stable towards liquid chemical and environmental attack