Experimental assessment of pigment dispersion in compounding of plastics: Rheological characterization at the crossover points

Abstract

Abstract Imparting colors to plastics is play a key role in the production of attractive products for a variety of consumer demands. It requires a good understanding of the processing conditions and formulation of compositions, including pigments and their dispersion. Key findings from these studies are studying the rheological characteristics of the compound of polycarbonate resins with different melt flow indexes and temperatures. The temperature was varied at three stages to study its effect on rheological characteristics and dispersions. The rheological behavior of grade was investigated using oscillatory rheometry at a variant temperatures, thereby improving the dispersion of pigments. Furthermore, it is determined that the crossover point (G″/G′) is considered as a good indication for higher pigment dispersion and lower color difference. However, the study will enable us to understand the dependence of the crossover points (G″/G′), which occurs at 255\u202f°C at (72.6\u202fHz, 1.82 X 10 5 P a ). It is determined that the moving of the crossover point to a higher frequency as the temperature increases to 255\u202f°C, is proportional to the temperature and higher shear rate. Lower viscosity improves pigment wetting, lowers color difference and ultimately results in higher dispersion occurs at or greater than the crossover point at 255\u202f°C. Furthermore, many conclusions found here can be used to optimize compounding materials, studied effects of rheology, looked at the effects of processing parameters on dispersion, pigment size distribution (PSD), and the morphology of pigments in polycarbonate compounds. In general, the total color difference decreased when processing parameters were increased. De-agglomeration occurred in zones of high shear and was found to significantly increase the number of particles and generate an efficient dispersion process, and hence reduce color mismatch so that wastage is minimized.