Non-Newtonian Rheology Lab Protocol & Data Sheet

Non-Newtonian rheology studies fluids whose viscosity varies with applied shear stress or shear rate—unlike Newtonian fluids (e.g., water or glycerol), which exhibit constant viscosity independent of deformation history. This lab protocol typically involves preparing model non-Newtonian fluids (e.g., aqueous polymer solutions like xanthan gum or carbopol, or colloidal suspensions), calibrating a controlled-stress or controlled-rate rotational rheometer, performing steady-state shear sweeps, and optionally conducting time-dependent tests (e.g., thixotropy or viscoelastic oscillatory measurements). Key principles include the distinction between shear-thinning (pseudoplastic), shear-thickening (dilatant), yield-stress (e.g., Bingham or Herschel–Bulkley), and time-dependent behaviors (thixotropic/ rheopectic). The data sheet supports systematic recording of instrument parameters (geometry, temperature, gap setting), raw torque/rotation data, computed shear stress (τ) and shear rate (γ̇), and subsequent model fitting (e.g., Power Law or Herschel–Bulkley regression). Applications span chemical process design, food processing (ketchup, yogurt), pharmaceutical formulation (suspensions, gels), and biomedical engineering (blood analogs, synovial fluid substitutes), where accurate rheological characterization informs pump selection, pipe sizing, mixing efficiency, and delivery device design.