Speaker:
Parth Uday Kelkar (Purdue University)
Title:
Scale Up Processing of structured complex fluids: Optimizing concentrated surfactant flow with In-line/ On-line technology
Authors:
Kelka, P. U. (Purdue University); Erk, K.A (Purdue University); Tozzi, E.J (The Procter & Gamble Company); Lindberg, S (The Procter & Gamble Company)
Abstact:
Cleaning products like shampoos and detergents contain a large amount of water, essential for their use but unnecessary for their production and transport. Since water in the shower dilutes these products effectively, shifting to concentrated formulations would significantly reduce waste and environmental impact. However, simply removing water alters the microstructure and can compromise product performance. Further, conventional production methods struggle to process these highly viscous pastes, making scale-up from the lab to manufacturing extremely challenging. Unless multiscale material relationships are established, industry will continue to waste resources on unsustainable manufacturing processes. Efficient processing requires accurate viscosity measurements in real time, as benchtop techniques may not fully capture variations under dynamic flow conditions. This university-industry collaboration developed fundamental relationships between rheology, microstructure, and processability of concentrated non-Newtonian solutions. An entangled aqueous polyvinyl alcohol (PVOH) solution and lamellar-structured concentrated (70 wt.%) sodium lauryl ether sulfate (SLE3S) paste were used as model fluids. By integrating offline and in-line/on-line techniques, flow behavior and the evolution of flow instabilities such as wall slip, shear banding, and plug flow across multiple scales were analyzed. Cross-polarized optical microscopy was used to characterize static and sheared microstructures. Lab-scale (offline) measurements using traditional benchtop rheometry and 1D velocity profiles from ultrasound speckle velocimetry (USV) were compared with in-line/on-line measurements in a pilot-scale pipe flow loop, where pressure-based viscosity was determined via soft sensors and velocity profiles were monitored in 2D using magnetic resonance imaging (MRI). The validity of offline measurements was assessed, revealing good agreement across all shear rates for low-yield-stress PVOH solutions. In contrast, for the highly viscous SLE3S paste, consistency between lab and pilot-scale measurements was observed only at high shear rates above 10 s⁻¹. Experiments exploring the effects of thixotropy, formulation aids (additives such as plasticizers), and processing equipment (such as static mixers) are ongoing. Outcomes from this study bridge the gap between lab-scale characterization and industrial processing, providing robust scale-up strategies for concentrated feedstocks and advancing the sustainable manufacturing of consumer cleaning products.

Speaker:
Hammad A. Faizi (The Dow Chemical Company)

Title:
Recombinant fibrous protein gels and functionalized polysaccharides as rheological modifiers in personal care formulations

Authors:

McMillan, J.R (Dow), Riley, J.K (Dow), Kamdar. S (Dow), Fernandez, A (Dow), Caruso, B (Dow), Leal, L (Dow), Britton D (NYU), Gao, W (Dow), Yin, L (Dow), Sun, J (NYU), Montclare, J.K (NYU)

Abstract:
Replacing petrochemical raw materials with bio-based ingredients that have improved end-of-life profiles without compromising performance remains a significant challenge for formulators in the personal care space. Rheological modifiers are crucial in developing multi-ingredient complex fluids. In this talk, I will focus on two areas in personal care: skin and hair care. First, I will discuss a coiled-coil protein hydrogel variant, Q5, for its pH-responsiveness, where physical cross-linking and material strength are controlled by pH relative to the isoelectric point (pI) of the protein. Q5 can retain a partial solution-to-gel transition at pH 6.0 and acts as a soft hydrogel by rheology. We tested Q5 as a rheological modifier in a standard skin cream at pH 6.0 and pH 8.0 to simulate conditions mediated by pH changes in the skin environment. Q5 uniquely increases material strength at low pH compared to hydroxyethyl cellulose (HEC), suggesting that protein-based coiled-coil rheological modifiers can be used in skin care. Additionally, the rise in consumer preference for non-sulfate shampoos poses challenges for viscosity modification via traditional worm-like-micelle (WLM) mechanisms due to the high positive curvature of many non-sulfate surfactants (e.g., alkyl glucoside and amino acids). This talk will transition to showcase how these challenges can be overcome using high-molecular-weight hydroxypropyl methylcellulose (HPMC) and biobased sulfate-free surfactants. We investigate the phase behavior of HPMCs with non-sulfate surfactant mixtures, highlighting the utility of hydrophobic interactions in enabling formulation stability. Comparing shear rheology to standard acrylate thickeners reveals the superior texture achievable with HPMCs in difficult-to-thicken surfactant systems. HPMC-surfactant complex rheology under extensional flow is also investigated using a Capillary Breakup Extensional Rheometer (CABER), which is crucial for consumer experience and formulation processing. We hope these findings will motivate industrial scientists to design better multicomponent formulations with a correct understanding of rheology, processing, and applications.