Rheology Laboratory

A state of the art rheology laboratory is available at the University of Toledo. This laboratory is dedicated to understanding and characterizing the flow of Newtonian and non-Newtonian complex fluids, including inks, crude oils and tar sands, biomass and gas hydrate slurries, polishing dispersions, polymer and polyelectrolyte solutions, polymer films, pastes, etc. A significant number of rheology accessories are available, which distinguishes our laboratory from other rheology laboratories. Methods include rotational and extensional rheometry, small angle scattering, high shear rheology, high pressure rheology, and controlled humidity rheological and mechanical measurements. If you are interesting in rheology testing, consulting, or other research needs, please contact Professor Liberatore.

Location

University of Toledo

Room 2021 North Engineering

1744 N Westwood Ave.

Toledo, OH 43606

MATERIALS OF INTEREST

The laboratory performs rheological testing, specifically steady shear (flow curves), oscillatory tests (elastic modulus, viscous modulus, and phase angle), tensile tests, transient flow experiments (creep and stress relaxation, yield stress). The following materials have been successfully characterized by our team in recent years: crude oil and mineral oils (heavy oils, bitumen, asphalts), polymer films including ion exchange membranes, polyelectrolyte and polymer solutions including wormlike micelle and drag reducing polymers, food and cosmetic products (suspensions, emulsions), methane and gas hydrate slurries, polishing materials, industrial and municipal wastewater sludge, biomass and pyrolysis oils including algae, and inks including carbon black and graphene.

IMPORTANT INSTRUMENTS

TA Instruments Discovery hybrid rheometer DHR-3

TA Instruments ARES G2 rheometer

XPlore microcompounder

Film coater

ACCESSORIES FOR DISCOVERY HYBRID RHEOMETER

The Peltier plate unit operates in the temperature range of -40 to 200ºC with several parallel plates and cones. Smooth and crosshatched surfaces are available. Solvent traps are available for each geometry. The solvent traps prevent evaporation of volatile samples and reduce interaction with the atmosphere. Changing diameter, cone angle, and surface finish allows measuring the widest range of material types and properties, e.g., from viscosities as low as water to viscosities as high as asphalts, from homogeneous single-phase fluids to multiphase mixtures. The Concentric cylinder unit controls temperature in the range from -20 to 150ºC and compatible with double-gap or standard rotors (for low viscosity materials) and vane rotors (for viscoelastic materials). A High pressure cell operates up to 2000 psi and from -10 to 150oC are based on a Peltier controlled concentric cylinder system with the inner bob driven with the use of a magnetic coupling. The cells can be hermetically attached to a stand-alone high-pressure mixing reactor through a syringe pump to perform external saturation/reaction/foaming of studied fluids. The high pressure assembly can be used for a wide range of studies, including rheology of gas saturated or live oil, foams, the formation, growth, aggregation, rearrangement, and dissociation of gas hydrates forming at high pressures and low temperatures in subsea oil and gas pipelines, etc. Rheo-optical accessories based on Small Angle Light Scattering (SALS) and patented by Prof. Liberatore allow visual tracking of structural changes in fluids under shear stress during the collection of rheological measurements.

ACCESSORIES FOR ARES RHEOMETER

A Forced Convection Oven, air/nitrogen gas convection, operates over the extremely wide temperature range of -150 to 600 °C with a maximum controlled heating rate of 1°C/s. The oven is compatible with many accessories. Rotational (parallel plates) geometries similar to those for AR G2 rheometers. A humidity control unit provides precise control of relative humidity inside the convection oven. Used for materials sensitive to atmospheric moisture and their degradation upon moisture exposure. Extensional (SER rotary clamps) geometry is used for conducting a range of rheological measurements such as tensile, peel, tear and friction measurements. This geometry measures properties of hard and soft solid films. Films with consistent, specified thickness for the extension measurements are produced with a film coater.

Chemical Engineering