Project ID: TECH2024-26
Background
Shear thickening refers to the phenomenon in rheology where the viscosity of a fluid increases as the rate at which the fluid is deformed by a shearing force (i.e., the shear rate) increases. When more force is applied to the fluid, the fluid becomes more resistant to flow. Shear thinning is when the viscosity decreases as the shear rate increases. Both shear thickening and shear thinning occur in non-Newtonian fluids as they have shear-dependent viscosity.
Shear thickening can complicate processing operations in numerous ways. Specifically, in the ceramics industry, shear thickening can lead to difficulties in forming and shaping clay-based materials, resulting in defects and inconsistencies in the final products. Similarly, in the paint and coating industries, shear thickening of kaolin dispersions can cause problems during mixing, pumping, and spraying processes and can result in uneven application and coverage, leading to defects, such as streaking and mottling on painted surfaces. Processing kaolin clay presents significant challenges, particularly due to shear thickening, which can cause various issues and challenges across different industrial applications. The formation of agglomerates during shear thickening can lead to increased wear on processing equipment and clogging of pipelines and nozzles which can disrupt production processes. Overall, addressing the challenges associated with shear thickening of kaolin clay is important for enhancing process efficiency and product quality in various industrial sectors, including ceramics, paints, and coatings. Additionally, shear thickening can lead to equipment clogging and increased wear and tear on processing machinery, resulting in downtime and maintenance issues. High viscosity, jamming, and shear thickening in particulate systems can cause processing difficulties.
One current solution to shear thickening is to use dispersions with lower solid content, but this leaves more solvent to deal with. Lower solid content can also worsen the performance of a clay, such as kaolin, by resulting in not enough coverage in coating, higher volatile organic content, and longer drying times. Thus, there remains a need in the art for new and improved strategies for overcoming the challenges associated with shear thickening.
Description
Researchers have identified way of shifting critical thickening shear rate of clay dispersions by adding spherical silica particles of various sized and concentrations. Compositions and methods involving clay and nanosilica are described in our patent application.
Applications
Advantages
IP Status: Patent Pending