In this work, the methodology for the optimal design, operation and scale‐up of reactive extrusion processes in twin‐screw extruders previously presented in Reference (Cegla and Engell, 2023). is applied to the production of hydrophobically ethoxylated urethanes (HEURs). The new process is a promising alternative to the current batch technology in large reactors with long residence times. We demonstrate the use of model‐based design and scale‐up for this case. A novel mechanistic finite volume twin‐screw extruder model is used as the process model, which is adapted to the process at hand by embedding a detailed description of the HEUR chemistry and rheology. An economic cost function is used to examine the scale‐up process from an 18 mm extruder to a 27 and 75 mm extruders, considering a selected range of products. The comparison between the optimization results obtained for the individual products with the optimization results for the production of multiple material grades using the same screw setup shows the high flexibility of the extruder‐based process. Significant energy savings compared with the conventional batch process can be achieved using reactive extrusion. To quantify the effort for the transition to a purely continuous production in terms of flexibility and process logistics, product changeovers are investigated.
Intensification of the HEUR production by reactive extrusion.
Detailed model for the twin‐screw extruder and the chemistry.
Optimization of extruder, screw design, and operating conditions.
Model‐based scale‐up from laboratory to industrial scale.
Investigation of flexible industrial production of different HEURs.


Optimal design and operation of reactive extrusion processes: Application to the production and scale‐up of polyurethane rheology modifiers for paints

In this contribution, Real-Time Optimization with Modifier Adaptation and Quadratic Approximation (MAWQA) is experimentally applied to a pilot-scale 18 mm reactive extruder for the production of hydrophobically modified ethoxylated urethanes which are used as rheological paint additives. Standard model-based control is in this application not applicable because of the complex coupling of the chemical reaction, complex internal flows within the equipment, and a high sensitivity to external disturbances. The optimization is performed with the goal to minimize the specific energy requirement for the product by changing the overall throughput and the barrel temperature locally while meeting a hard constraint on the product quality. The product quality is determined by the viscosity of the product which is measured online with a capillary viscometer. In contrast to other work, the MAWQA method is applied here purely data-based without using a physical model. Despite the absence of a rigorous model, the method converged to the optimum after 6 initial probing moves and 4 iterations where the product quality constraints were already met. 

Experimental Application of Real-Time Optimization with Modifier Adaptation and Quadratic Approximation to a Reactive Extrusion Process

One-Step versus Two-Step Synthesis of Hydrophobically Modified Ethoxylated Urethanes: Benefits and Limitations

A novel investigation of the effects of the hydrophilic and hydrophobic segments of hydrophobically modified ethoxylated urethanes (HEURs) on the rheological properties of their aqueous solutions, latex-based emulsions, and waterborne paints is demonstrated. Different HEUR thickeners were produced by varying the poly(ethylene glycol) (PEG) molecular weight and terminal hydrophobic size. Results reveal that the strength of hydrophobic associations and, consequently, the rheological properties of HEUR formulations can be effectively controlled by modifying the structure of the hydrophobic segment, specifically, the combination of diisocyanate and monoalcohol. This allows for the on-demand attainment of diverse rheological behaviors ranging from predominantly Newtonian profiles exhibiting lower viscosities to markedly pseudoplastic behaviors with significantly higher viscosities. The length of the hydrophilic group appears to affect viscosity only marginally up to a molecular weight of 23,000 g/mol, with more notable effects at 33,000 g/mol. Additionally, it was indicated that the rheological responses observed in water solutions provide a reliable forecast of their behavior in latex-based emulsions and waterborne paints. Coarse-grained molecular dynamics (CG-MD) simulations were also applied to gain insight into HEUR micelle dynamics in aqueous solutions. Guided by the DBSCAN algorithm, the simulations successfully captured the concentration-dependent behavior and the impact of hydrophilic chain length, aligning with the experimental viscosity trends. Various metrics were employed to provide a comprehensive analysis of the micellization process, including the hydrophobic cluster volume, the total micellar volume, the aggregation number, and the number of chains interconnecting with other micelles.

Tailoring Waterborne Coating Rheology with Hydrophobically Modified Ethoxylated Urethanes (HEURs): Molecular Architecture Insights Supported by CG-MD Simulations

Hydrophobically modified ethoxylated urethanes (HEURs) are among the most widely studied class of waterborne polyurethanes. HEURs are amphiphilic polymers that are usually composed of a polyethylene glycol (PEG) backbone, typically end-capped with aliphatic alkyl chains. HEUR synthesis in the industry is a slow and energy-intensive step-growth polymerization process, due to heat and mass transfer limitations inherent in such highly viscous systems. We investigate for the first time the effect of microwave heating on both the solvent-free HEUR synthesis step and the initial pretreatment step of the reagents prior to the HEUR synthesis. We show that microwaves can drastically reduce the overall processing time, and thereby reduce total energy consumption by: A) faster melting of solid PEG and B) faster completion of the polymerization reaction, when operating with a novel rapidly rising transient temperature profile that cannot be reproduced by conventional heating. However, it was found that PEG pretreatment/dehydration by microwaves leads to faster degradation of PEG, compared to dehydration by conventional heating at the same bulk temperature, and should therefore be avoided. 

Intensification of Solventless Production of Hydrophobically-modified Ethoxylated Urethanes (HEURs) by Microwave Heating

: The steel manufacturing industry is one of the most concentrated anthropogenic carbon-emitting point sources that is still expected to increase further each year. Moreover, steel slags are also generated at a rate of 10–20% of the total crude steel production. The possibility to valorize both the ﬂue gases and steel slags through mineral carbonation has garnered the spotlight in recent research on waste valorization and sustainable steel production practices. Mineral carbonation of steel slags leads to the stable adsorption of carbon dioxide onto the surface of the steel slags. Nonetheless, it is essential to assess whether the environmental beneﬁts resulting from the mineral carbonation process would outweigh the environmental burdens associated with the transformation and carbonation processes. To this end, this study aims to illustrate the potential environmentally friendly industrial waste valorization pathway by performing life cycle assessment (LCA) to obtain the environmental impacts of carbonated steel slags. The environmental impacts are calculated by the ReCiPe 2016 midpoint methodology. Furthermore, contribution analysis for the carbonated slag production is provided. This study also illustrates a comparison of steel slag carbonation with pure carbon and ﬂue gases by means of scenario analysis. The results of this study should provide insights into the possibility of employing mineral carbonation on industrial wastes in the metallurgical sector as well as highlight the possible areas of improvement for prospective scale-ups. To this end, the results of this study could contribute to the improvement of the environmental sustainability of the steel manufacturing sector.

Preliminary Environmental Assessment of Carbonated Slags as a Carbon Capture, Utilization, and Storage Materials (CCUS)

Preliminary Environmental and Economic Assessment of Mineral Carbonation of Steel Slags as a Carbon Capture, Utilization and Storage Technology

In this work, we report for the first time on the influence of the quality of reactants and reaction conditions on the production of hydrophobically modified ethoxylated urethanes (HEURs) and selected prepolymers without the use of solvents. We show that the polyol water concentration is detrimental to the progress of the main urethane forming reaction, confirming the necessity of carefully drying the reactants below 1000 ppm to suppress the consumption of diisocyanate toward urea during HEUR synthesis. Increasing the mixing speed (≈30 to 750 rpm), reaction temperature (80–110 °C), and catalyst concentration (0.035–2.1 wt % bismuth carboxylate) can significantly increase the rate of molecular weight buildup, but their effect decreases with time as the bulk viscosity increases and mixing limitations eventually take over, leading to the Weissenberg effect and chain growth termination. Consequently, for the selected formulation, the maximum product molecular weight attained lies in the range of ≈20 000–22 000 g/mol, irrespective of the specific process conditions applied.

Insight Into Solventless Production of Hydrophobically Modified Ethoxylated Urethanes (HEURs): The Role of Moisture Concentration, Reaction Temperature, and Mixing Efficiency

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Anthony de Schutter

Author Tools

Chat about Author

Papers

Preliminary Environmental Assessment of Carbonated Slags as a Carbon Capture, Utilization, and Storage Materials (CCUS)

Preliminary Environmental and Economic Assessment of Mineral Carbonation of Steel Slags as a Carbon Capture, Utilization and Storage Technology

Insight Into Solventless Production of Hydrophobically Modified Ethoxylated Urethanes (HEURs): The Role of Moisture Concentration, Reaction Temperature, and Mixing Efficiency