Rheological\nProperties of Dense Particle Suspensions\nof Starches: Shear Thickening, Shear Jamming, and Shock Absorption\nProperties

Concentrated suspensions of Brownian and non-Brownian\nparticles\ndisplay distinctive rheological behavior highly dependent on shear\nrate and shear stress. Cornstarch suspensions, composed of starch\nparticles from corn plants, served as a model for concentrated non-Brownian\nsuspensions, demonstrating discontinuous shear thickening (DST) and\ndynamic shear jamming (SJ). However, starch particles from other plant\nsources have not yet been investigated, despite their different sizes\nand shapes. This study is focused on the evaluation of the effects\nof the structural parameters of starch particles by preparing concentrated\nsuspensions of starch particles from 13 different plants at particle\nfractions of 25–50% and their rheological behavior through\nsteady shear, pull-out, and ball-drop tests. Starch particles can\nbe roughly classified as polygonal and ellipsoidal. The DST and SJ\nbehavior typically reported for concentrated cornstarch suspensions\nwere confirmed for other starch particles in both particle groups.\nThe ball-drop test demonstrated excellent shock absorption properties\nfor 11 concentrated suspensions of starch particles, except for sago\npalms. In the case of concentrated suspensions of starch particles,\nthe particle fraction and shear applied were the dominant factors\nthat significantly affected the rheological behavior, whereas the\nparticle shape was not a primary contributor. The findings of this\nstudy drive further investigation on the effect of liquid and particle\nsurface properties in concentrated particle suspensions on DST and\nSJ behaviors.