Effect of the pigment concentration on the dimensional stability and the melt flow index of polycarbonate

Abstract

This study is focused on the effect of pigments on polycarbonate (PC), especially the dimensional stability and flow properties of this material. This polymer is commonly used in the plastics industry and the most common processing of this polymer is injection molding technology. Three different pigments made by Lifocolor company were selected for PC staining. In addition, six different concentrations of aforementioned pigments were used. It is worthwhile to note that the pigments in the polymer matrix acted as a filler. Just like fillers, the pigments also influence the shrinkage of the polymer in both the main and secondary directions. The paper also deals with the effect of pigment concentration on the melt index (MFI). It was shown that the presence of pigments reduces the thermal mobility of the macromolecular chain. Melt flow index changes were also directly tied to the changes of the viscosity, which was also affected by the pigments. It can be expected that the viscosity might not remain the same even at varying shear rates. © 2019. Published by Manufacturing Technology.