Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Polymer blends with optimized properties: influence of processing and additives on phase behaviour

Polymer blends are materials possessing a combination of desired properties, according to customer needs, based on low-cost widely available commodity polymers. The challenge in designing and producing such materials is to control the morphology, particularly during processing. Structure essentially determines the final properties and depends on blend components and additives. Therefore, understanding the interplay of morphology, chemical structure and processing characteristics is absolutely necessary.

This project has aimed to contribute in this direction with three specific objectives of fundamental, as well as practical, significance: thorough characterization of phase state and dynamics; effects of shear flow and/or additives on the phase behaviour; thermodynamic modelling of shear-induced structural changes in binary or ternary systems.

The above goals have been successfully met, and the main accomplishments of this project can be summarized below as follows:
An experimental toolbox has been developed for the systematic characterization of the phase behaviour of polymer blends;
Flow-light experiments showed the occurrence of shear-induced demixing and mixing, depending on shear rates, temperature and dynamic asymmetry between constituents;
Using the concept of a generalized Gibbs energy of mixing, a multitude of phenomena (shear-induced homogenization, shear-induced demixing, inversion of the effects plus the occurrence of islands of immiscibility) have been predicted for flowing binary or ternary polymer blends;
The synthetic efforts yielded a graft copolymer compatibilizer for the industrial SMA/PMMA blends. This important development opens the route for the industrial-scale synthesis of additives of controlled microstructure for various applications.

Reported by

Foundation for Research and Technology Hellas (FORTH)
Vassilika Vouton
71110 Heraklion
Greece