Particle size analysis of plasticized PVC dispersion resins using the photometric centrifugal sedimentation method

There are many known methods for determining the particle size distribution of PVC dispersion resins. Most of these methods require that the resin be in an aqueous medium. PVC dispersion resins are used primarily in a plasticizer medium. The shearing action that takes place when the resin is mixed in plasticizer and the subsequent solvating action of the plasticizer affect the particle size distribution of the dispersion resin. It is advantageous to be able to determine the particle size distribution of the plasticized resin since it can affect various properties such as rheology, gloss and foam quality. It is the purpose of this paper to show that a fast zonal sedimentation technique can be used to analyze the less than 20 μ particle size fraction of a dispersion resin after it has been mixed in a plasticizer system. This can be accomplished in less than 90 minutes. This technique can be used to relate particular dispersion resin properties to the particle size distribution of the resin. The method can also be used as a quality control test.