Abstract
A model estimating the time-dependent distribution of cluster size consisting of fine particles in Newtonian molten polymer has been improved. The present model for agglomerative suspension was developed based on Usui's thixotropy model, derived by taking the balance between shear breakup, shear coagulation and Brownian coagulation process. The interparticle bonding energy in the model was assumed as a function of a cluster size in this study though it was assumed to be constant in the previous study. The analysis was applied to the experimental results for silica/(ethylene methyl-meta acrylate copolymer) suspensions. The time variation of cluster size distributions, of viscosities and of the mean number of particles in a cluster was calculated and the results were compared with experimental results mainly for the cases of the solid volume fractions from 0.10 to 0.25 when the shear rate was changed from 0.2 to 10 s-1. From the results, it was found that the present model could estimate well the time dependency of cluster size distributions in a wide range of shear rate when the solid volume fraction was set at 0.15, and that the effect of the solid volume fraction was also sufficiently explained by the present model.
