The Rheology Behavior of Aramid and Cellulose Nanowhisker Suspensions

Abstract

The flow responses of aramid and cellulose nanowhisker (fibrids) or CNCs (cellulose nanocrystal) suspended in a sulfuric acid and water respect at loadings of about 17% weight fraction was determined in transient shear flow. The effect of temperature and shearing conditions were examined. Aramid solution exhibits strong shear thinning with power-law indices of about 0.2-0.3, and cellulose nanowhisker suspension indices is below 0.15. Formation of an interacting flocculated network at rest is the reason for the large relative viscosity and offers the least flow resistance during shear flow. The structure formed at rest is easily destroyed, and this is the reason for the observed shear thinning. Evolution of shear stress data versus time over four of shear rate were described the structure of nematic phase in aramid\sulfuric acid solution. Also, nanowhisker/water suspension shear rheology results show shear thinning behavior, and behave as a plastic system at different temperatures. For the spinning process, the aramid\sulfuric acid dope through the air gap entered cold water. Orientation of polymer solution emerged from the spinneret and, through very high extensional shear in the air gap, resulted in excellent tensile properties of the final spun fibers. © Amir Kaveh, Omid Moini Jazani, Morteza Ahmadi Lashaki, Mehrzad Mortezaee, Mahmoud Razavizadeh.