Rheology and Pipeline Flow Behavior of Starch Nanoparticle Dispersions

Starch nanoparticles (SNPs) are potentially very useful materials in nanotechnology applications not only because they are renewable, biocompatible, and biodegradable with the perspective of sustainable development, but also because of their unique properties at the nanoscale. However, systematic studies of the basic physical properties, rheology and pipeline flow behavior of dispersions of starch nanoparticles are lacking. In this study, the particle size distribution and the swelling characteristics of starch nanoparticles along with the rheology and pumping behavior of dispersions of starch nanoparticles are investigated experimentally. It is found that the SNPs undergo severe swelling when they are dispersed in the aqueous phase. The size distribution of starch nanoparticles shifts toward a larger size with the increase in the mass fraction of nanoparticles due to temporary aggregation of SNPs. The rheological behavior of SNP dispersions is nearly Newtonian within the ranges of SNP concentration (0-35 wt%) and temperature (20-80 degrees C) investigated in this work. The viscosity of SNP suspension decreases with the increase in temperature and increases with the increase in SNP concentration. The pumping behavior of SNP dispersion is similar to single-phase Newtonian fluids although some degree of drag reduction is observed in the turbulent regime.