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The Glass Transition Temperature of Heterogeneous Biopolymer Systems
Suellen Pereira Espíndola1, Ben Norder1, Ger J M Koper1
1Advanced Soft Matter, Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.
Biomacromolecules
|March 8, 2023
Summary
A new generalized mean model accurately describes plasticizer behavior in biopolymers, revealing heterogeneous material properties and enabling better material design for renewable resources.
Area of Science:
- Polymer Science
- Materials Science
- Biomaterials Engineering
Background:
- Biopolymers offer sustainable alternatives but often require plasticizers to improve properties.
- Existing thermodynamic models for plasticization are often phenomenological and lack predictive power regarding miscibility and sample history.
- Understanding structure-property relationships is crucial for optimizing bio-based material performance.
Purpose of the Study:
- To introduce a novel thermodynamic model, the generalized mean model, for describing plasticization in semi-compatible polymer systems.
- To analyze diluent segregation and partitioning using the model's constant, k_GM.
- To validate the model's applicability across various plasticized (bio)polymer systems.
Main Methods:
- Development of the generalized mean model incorporating diluent partitioning.
- Analysis of the k_GM parameter to classify plasticization effects (anti-plasticization vs. high plasticization).
- Experimental study of sodium-alginate films plasticized with sugar alcohols of varying sizes.
- Modeling of literature data for other plasticized polymer systems.
Main Results:
- The generalized mean model effectively classifies diluent behavior, distinguishing between systems with minimal plasticizer effect (k_GM < 1) and those with significant plasticization (k_GM > 1).
- Sodium-alginate films showed properties dependent on polymer interactions and morphological effects, as indicated by k_GM analysis.
- The model's application to literature data confirmed a general heterogeneous nature in plasticized (bio)polymer systems.
Conclusions:
- The generalized mean model provides a robust framework for understanding and predicting plasticization in semi-compatible systems.
- Material heterogeneity is a common characteristic of plasticized (bio)polymers, influencing macroscopic properties.
- The model facilitates structure-property relationship analysis, aiding in the design of advanced bio-based materials.
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