Analysis of thermomechanical properties and morphology of polyethylene pipes after aging by UV radiation
Polimery 2014, No 4, 308
This paper presents the results of an assessment of structure and thermomechanical properties of polyethylene before and after the aging by UV irradiation. The test specimens were cut from the pipes manufactured by extrusion. They were analyzed using dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and microscopic examination at 400× magnification. The hardness, colour and gloss of the specimens were also investigated. It was shown that UV radiation induces irreversible changes in polyethylene leading to deterioration of polymer mechanical properties i.e. a decrease of storage modulus and mechanical loss tangent values. Polyethylene samples exhibit a lower degree of crystallization, reduced hardness and tensile strength as well as changed gloss and colour tone after UV aging. Also, a slight reduction in the size of spherulites was observed in microscopy investigations.