Predicting miscibility in polymer blends using the Bagley plot: Blends with poly (ethylene oxide)

Significance Statement

Polymer blending is an interesting approach for developing new polymeric materials with unique properties. However, polymer blends are mostly immiscible. In fact, miscible polymers are in most cases considered as exceptional cases owing to the general rule of polymer immiscibility. Above all, investigating miscibility of polymers is quite difficult in a practical sense. Such difficulties emanate from high viscosity of the species, which tend to cause thermal degradation during processing, and low diffusion towards equilibrium.

Spanish researchers led by professor Emilio Meaurio at the university of the Basque Country obtained Bagley miscibility maps of polymer blends with poly(ethylene oxide) using current group contribution methods. The calculated solubility parameters were graphed in a Bagley plot and were used to inquire miscibility regions through comparison with the experimental results obtained from miscibility analyses. Their work is published in peer-reviewed journal, polymer.

The authors built Bagley plots for poly(ethylene oxide) blends by applying solubility parameters computed according to the group contribution methods developed by Hoftyzer-Van Krevelen, Hoy and Stefanis-Panayiotou. They also used the Yamamoto-Molecular Break (Y-MB) method implemented in the Hansen Solubility Parameters in Practice (HSPiP) software, which creates automatically first-order UNIFAC functional groups and applies an adaptive Neural Network methodology to account for inter-group interactions. They selected the poly(ethylene oxide) blends owing to its miscibility with a good number of miscible and immiscible polymeric materials. This allowed them to have a good representation of its solubility map with the appropriate information. The authors also obtained an additional Bagley plot by applying the miscibility parameters from solubility tests.

The authors observed that the plot obtained from solubility parameters assuming the Hoftyzer-Van Krevelen group contribution method indicating that miscible systems create circular region of 2.5MPa1/2 around poly(ethylene oxide). Poly(ethylene oxide) is considered a non auto-associated polymeric material with accessible and strong acceptor groups. Therefore, its radius can be expected to be larger when compared to other polymers. In case the counterpart polymers contain complementary groups, miscibility can be achieved at larger distances. Complementary groups can establish hydrogen bond interactions with the ether groups of poly(ethylene oxide).

The authors realized that the Bagley plot from the parameters of the Hoy method had an expected behavior as most points followed a curvilinear trend. The total solubility parameters from this group contribution method were reliable, but the procedure to obtain the partial components was questionable. The research team therefore resolved that developing a Bagley plot to test the miscibility of polymer blends using this group contribution method may not offer much advantage over using the total solubility parameters directly.

They were able to analyze in their work a Bagley plot developed using experimental miscibility parameters drawn from solvent testing analyses. Unfortunately, this was also unable to define the miscibility around poly(ethylene oxide). However, the solubility parameter approach offers a simple and useful route to analyzing polymer miscibility. The success of the authors was pegged at the correct implementation of the proposed method, specifically in determining the solubility parameters of the polymers involved in the blend.

This study explored comprehensively the methods available for the application of the solubility parameters approach in a bid to predict the miscibility of polymer-polymer blends using blends with poly(ethylene oxide). The cloud of points obtained helped them to draw conclusions about coherent as well as the accuracy of every method used to obtain the miscibility parameters.

This paper analyzes the current procedures to predict polymer miscibility based on the solubility parameter approach.

Predicting miscibility in polymer blends using Bagley plot Blends with poly (ethylene oxide) - advances in engineering

About the author

Dr. Ainhoa Lejardi is an associate professor in the School of Engineering of Bilbao in the Materials Engineering department. She received his PhD in Materials Engineering in 2011 from the university of Basque Country (UPV-EHU). She collaborates in the ZIBIO research group, integrated in POLYMAT, which is a well known center within the Basque Foundation for Science, IKERBASQUE. His research interests focus on biodegradable polymers, miscibility of polymers and hydrogels.

About the author

Dr. Andrea Sánchez Camargo is B.Eng. in Chemical Engineering by National University of Colombia (2006) and M.Sc. in Food Engineering by University of Campinas (Brazil, 2010). Recently, she has finished her Ph.D. studies in Biology and Food Science at Autonomous University of Madrid (Spain, 2017) in the Research Institute of Food Science (CIAL-CSIC). Her background includes research experience in both scientific and industrial scenarios. She has published 19 papers in indexed journals.

Her research interest are in the areas of green processes, high pressure extraction technologies, Hansen solubility parameters, bioactive compounds and advanced analytical techniques (LCxLC- MS/MS, GC-MS, LC-MS-qTOF).

About the author

Dr. Emilio Meaurio obtained his B.S. in Chemistry in 1991 and his Ph.D. in 1996 from University of the Basque Country (EHU). He was Professor of the “Polymer Engineering” degree in the Lea-Artibai School (1997-2002) and is currently full Professor in the University of the Basque country. He collaborates in the ZIBIO research group and has published over 50 research papers in indexed journals in the fields of Polymer Science and Physical Chemistry.

His research interests are in the areas of biodegradable polymers, polymer blends, analysis by FTIR spectroscopy of interactions and crystalline structures, and molecular modeling.

About the author

Dr. Ester Zuza earned two B.S.: Chemistry with specialty in macromolecules in 2000 and Materials Engineering in 2004. She got her Ph.D. in 2009 from University of the Basque Country (EHU). She has published over 20 research papers in indexed journals in the fields of Polymer Science and Biomedical Engineering. She collaborates in the ZIBIO research group and POLYMAT.

Her current research interests include biodegradable polymers, polymer blends, composites, physical and chemical characterization and mechanical properties.

About the author

Eva Sánchez Rexach is currently a PhD student within the Doctoral program “Engineering of Materials and Sustainable Processes”. She earned her technical certificate in Industrial Chemistry, her degree in Industrial Organization and her MSc in Advanced Materials Engineering from the University of the Basque Country (UPV/EHU).

Her current research topics are focused on controlled drug release systems based on biodegradable polymers, as part of ZIBIO research group that research on biodegradable synthetic polyester systems for biomedical applications.

About the author

Jose-Ramon Sarasua is professor of Materials Science at the department of Mining-Metallurgy Engineering and Materials Science, Faculty of Engineering of Bilbao, the University of the Basque Country (UPV/EHU). He is the principal investigator of the ZIBIO group on Science and Engineering of Polymeric Biomaterials and member of POLYMAT, the Basque Center for Macromolecular Design & Engineering.

His research interests are focused on the synthesis, structure and properties of polymeric biomaterials for medical applications.


Emilio Meaurio1, Eva Sanchez-Rexach1, Ester Zuza1, Ainhoa Lejardi1, Andrea del Pilar Sanchez-Camargo2, and Jose-Ramon Sarasua1. Predicting miscibility in polymer blends using the Bagley plot: Blends with poly (ethylene oxide). Polymer, volume 113 (2017), pages 295-309.

Show Affiliations
  1. Department of Mining-Metallurgy Engineering and Materials Science, POLYMAT, University of the Basque Country (UPV/EHU), School of Engineering, Alameda de Urquijo s/n, Bilbao, Spain.
  2. Laboratory of Foodomics, Bioactivity and Food Analysis Department, Institute of Food Science Research, CIAL (UAM-CSIC), C/Nicolas Cabrera 9, Campus UAM Cantoblanco, 28049 Madrid, Spain.


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