Compaction Physics Of Solid Additive Blends : A Thermal Properties Study

Abstract

Compacted solid additive blends have attracted the interest of the polymers industry due to their ability to improve processability. However, limited research has been performed to analyze the thermal properties that these additives have during pelletization.This research studies the reaction behavior of erucamide and silica, when in a pure and mixed form, with each other when thermal conductivity and frictional heating experiments are conducted. During the thermal conductivity study, it was found that pure erucamide had a thermal conductivity of 0.37 W/mK. The thermal conductivity of pure silica could not be found since silica will not compact to itself. Therefore, the thermal conductivity was extrapolated and found to be 0.09 W/mK. With the higher thermal conductivity belonging to erucamide, the heat transference that occurs during pelletization is through the use of erucamide. During the frictional studies, it was found that erucamide had a lower coefficient of friction compared to silica. The samples used were not pure, meaning a presence of both silica and erucamide were present for all experiments. The value obtained for the sample with a 75wt% of erucamide was 0.26. The value obtained for the sample with 75wt% of silica was 0.53. The surface and cross-section morphology and composition of the samples was examined by Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy. Through this a softened layer was seen that provided evidence of an outer protective layer that forms during the pelletization process. Further analysis into this formed softened layer for varying compositions provided critical temperatures that need to be reached during processing.