Modelling and control of the microstructure of comb-like poly (MAA-co-PEGMA) water-soluble copolymers

Significance 

The use of water-soluble copolymers in multiple applications has rapidly increased over the past decades. In the construction and building industry, for example, the high viscosity of the mixture has resulted in low concrete performance. However, the addition of poly (MAA-co-PEGMA) copolymers otherwise known as superplasticizers has been identified as a promising solution for reducing the mixing water for a given density. Even though superplasticizer agents have been widely used in the construction industry, there is a great need to improve their performance, structure, and characteristics to fit the ever-changing construction needs.

Developed in the late nineteenth century, polycarboxylic ethers (PCEs) with a comb-like structure have highly improved the concrete performance by allowing large water reduction in the mixing process. Recently, their chemical structure has been improved to solve various problems associated with acidic monomers to meet specific market demands. Presently, two main processes: esterification and free radical copolymerization are commonly used to synthesis polycarboxylic ethers. Unfortunately, they cannot produce polycarboxylic ethers with desirable microstructure, which is a vital factor affecting concrete performance.

In a recent paper published in the Polymer Chemistry journal, University of the Basque Country researchers: Iñaki Emaldi (PhD candidate), Dr. Shaghayegh Hamzehlou, Dr. Edurne Erkizia, Dr. Jorge Sanchez Dolado, Dr. Agustin Etxeberria, and led by professor Jose Ramon Leiza investigated the interaction between the comb-like copolymers on the surface of cementitious materials. Fundamentally, the authors employed am open-loop control strategies: monomer starved and optimal addition methods to produce homogenous composition copolymers.

To ensure effective optical feeding strategies for copolymerization of MAA and PEGMA5 in alkaline aqueous solution, a detailed kinetic knowledge on the copolymerization process was necessary. Thus, a detailed mathematical model was developed. Based on the batch copolymerization experimental kinetic data, the unknown kinetic parameters were estimated. Next, the model was used to develop optimal feedings strategies. Eventually, its feasibility in synthesizing poly (MAA-PEGMA5) copolymers with uniform composition within the shortest possible reaction time was demonstrated and compared with the copolymers obtained using the conventional monomer-starved conditions.

Copolymer composition is a very essential feature controlling the charge density of the macromolecules in aqueous solutions. From the experiments, the authors demonstrated the inability of the monomer starved feed strategy and batch copolymerization method to produce homogenous copolymers. This was attributed to the deviation of a substantial copolymer chain fraction from the desired composition. This drawback was, however, addressed by the introduced mathematical model. As such, poly (MAA-PEGMA5) copolymers with desired homogenous compositions i.e. 2/1, 3/1 and 4/1 compositions were successfully synthesized. This was also achieved within the shortest reaction time as compared to the copolymers synthesized through conventional processes.

In addition to enhancing the homogeneity of copolymer composition, the strategy also significantly reduced the processing time. The study will, therefore, pave way for synthesizing MAA-co-PEGMA5 copolymers with high precision composition control. This will additionally lead to a proper understanding of the effects of microstructural features in aqueous solution and their corresponding interaction with cementitious particles thus advancing their construction applications.

 microstructure of comb-like poly (MAA-co-PEGMA) water-soluble copolymers - Advances in Engineering

About the author

Dr. Jose Ramon Leiza is Professor of Chemical Engineering at the school of Chemistry of the University of the Basque Country (UPV/EHU) and Director of the Institute of Polymer Materials, POLYMAT.

He graduated in Chemistry in 1987 and obtained the Ph.D. degree in Chemical Engineering in 1991 at UPV/EHU.

He spent sabbatical years at Lehigh University (USA) as Visiting Research Associate (1994-95) and Queen’s University (Canada) as a Visiting Professor (2004-05).

Awards: Rhone-Poulenc award in Clean Technologies (1993). Association of Engineers of Madrid.

His research focuses on the analysis of industrially relevant polymerization processes with especial interest on polymer reaction engineering aspects of polymerization in dispersed media. Thus, he has developed advanced control strategies for tailor making the microstructure and morphology of waterborne polymer dispersions. He is also involved in the research of the incorporation of inorganic nanoparticles into waterborne polymeric dispersions with advanced properties (UV absorption, photocatalysis, corrosion resistance, fluorescence emission) with applications on adhesives, coatings, paints, water treatment and sensors.

He has published more than 160 papers, 19 book chapters and delivered 27 invited talks and more than 170 poster and oral presentations in international conferences. He has coauthored 6 patents and has supervised 20 PhDs. He is member of the editorial boards of the Macromolecular Reaction Engineering (2010-) and International Journal of Polymer Science (2008-2016) journals. He co-chaired and organized the International Polymer Colloids Group conference in 2017 (IPCG2017) and vice-chaired the Polymer Reaction Engineering conference (PRE10) in 2018.

About the author

Iñaki Emaldi obtained his BSc in the University of the Basque Country in 2013. He spent one academic year with the Erasmus Programme in the Manchester Metropolitan University (United Kingdom) from September 2012 until June 2013. During that year he carried out a research project in the Faculty of Science and Engineering under the supervision of Dr. Chris Liauw.

During 2013-2014 he carried out MSc by Research in the Manchester Metropolitan University where he investigated the Use of Polypropylene for Rotational Moulding Applications under the supervision of Dr. Liauw and Pr. Potgieter.

Since February 2015, he is doing his PhD in POLYMAT in collaboration with TECNALIA under the supervision of Prof. Jose Ramon Leiza (UPV/EHU) and Dr. Edurne Erkizia (TECNALIA). The main objective of this project was to study the fundamental effects of the interaction of the model MPEG-PCE macromolecules and the cement particles. Therefore, the project consisted firstly on the controlled synthesis by free radical copolymerization of MAA and PEGMA macromonomers and characterization of their microstructure. The microstructure of the PCE’s macromolecules will be defined by the backbone length, the side chain length or the amount of side chain or anionic carboxylic groups in the backbone. Once the microstructure was characterized, establishing fundamental knowledge on the structure-property relationship was the aim. For this purpose, ordinary Portland cements and different clinker phases present in OPC were used.

About the author

Dr. Shaghayegh Hamzehlou earned her B.Sc. and M.Sc. in polymer engineering at Amir Kabir University of Technology (Poly Technique of Tehran) on 2006. Later, she worked for 4 years as R&D Engineer in a manufacturing company, working on polymer based insulation materials for high voltage generators. In 2010, she moved to University of Basque country to do the PhD in the framework of a European project, Marie Curie training network ITN NANOPOLY. In 2014, she joined Basque Center for Macromolecular Design and Engineering as a postdoctoral fellow involving in a European project RECOBA for 3 years. Currently she is working as a researcher at University of Basque Country.

Her research is focused on polymer reaction engineering, modelling and simulation of kinetics, topology, microstructure and morphology of the complex polymerization systems. She has (co)authored more than 20 scientific articles, 1 book chapter and had oral presentations in more than 20 national and international conferences and was a keynote lecturer at the Polymer Reaction Engineering X (PRE 10) May 20-25, 2018.

About the author

Edurne Erkizia has a PhD in Chemistry and she is a research scientist in the CEMPRO team within the Building Technologies Division of TECNALIA, a research center located in the Basque Country in northern Spain. This group aims to develop innovative and sustainable materials for the construction field, focusing mainly in the improvement of the properties and durability of cement-based materials.

Dr. Erkizia´s research has been focused in the synthesis of micro and nanoparticles by sol-gel chemistry and hydrothermal reactions to use them as additions in cement-based materials. She has participated in a number of different research projects related to the improvement of cementitious based materials at an international as well as national level and she has taken part as inventor in several patents. She is the author of several scientific papers and conference presentations.

About the author

Agustin Etxeberria is an assistant professor in the POLYMAT-Polymer Science and Technology Department of the University of the Basque Country (Faculty of Chemistry). He received the BS and PhD from the same University at 1987 and 1993, respectively. His current research interests are the developing of the novel materials for packaging as well as the polymer characterization by nuclear magnetic resonance.

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About the author

Jorge S. Dolado. Dr. in Physics by the Basque Country University (UPV/EHU), he has been researcher at different R+D institutes like TECNALIA, the CNRS and TU Delft, before getting a permanent position at the Spanish Research Council (CSIC). He is currently the Head of the Ceramic and Cement based Materials (C2M) group at the Centre for Materials Physics (CFM, CSIC-UPV/EHU). His scientific activity focuses mainly on the study of cement and related materials from a material science point of view with the aim of generating basic and applied knowledge.

Among the different lines of his research, it is worth mentioning: (i) the pioneering use of atomistic and colloidal simulations to study the structure and properties of cementitious materials (ii) the implementation of new hydrothermal and supercritical fluids (SCF) technologies for the ultra-fast synthesis of cementitious nanoparticles or (iii) the development of new cement clinkerization methods through the use of autoclaves or microwaves that allows a notable energy saving and a drastic reduction of CO2 emissions.

Reference

Emaldi, I., Hamzehlou, S., Erkizia, E., Sanchez Dolado, J., Etxeberria, A., & Leiza, J. (2019). Modelling and control of the microstructure of comb-like poly (MAA-co-PEGMA) water-soluble copolymers. Polymer Chemistry, 10(8), 1000-1009.

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