Effect of mould pressurisation on impact strength of rotationally moulded polyethylenes

The present paper describes trials that were carried out on a conventional and a metallocene linear low density polyethylene to determine the effect of bubble content on the impact performance of rotationally moulded parts. Internal mould pressurisation was applied at different levels and at different internal air temperatures during the moulding cycle. The quantity of bubbles in the different mouldings was determined and related to impact performance at room temperature and at -40 degrees C. Variations in dynamic mechanical properties were also highlighted.