Thermal analysis of the rotational molding cycle followed by internal air temperature profiles: an application for foamed polyethylene

In this study, temperature profiles for the air inside the mold was measured to analyze the thermal behavior of a polymer for a complete rotational molding cycle. Foamed and unfoamed linear medium density polyethylene (LMDPE) parts were produced by biaxial rotational molding. A chemical blowing agent (azodicarbonamide, ACA) was used at different concentrations (0, 0.25, 0.50, and 1.0 % wt.). The temperature profiles inside the mold were measured for different oven temperatures (260-320 C). The analysis proposed is based on the temperature profiles and their derivatives to better determine the different temperature transitions occurring in a complete molding cycle.