Unexplored Dimensions of Processing Phase Inversion during Polymer Melt Blending

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Blending of multiple polymers is a commonly utilized strategy to achieve a balance of a variety of critical properties of polymeric materials, such as strength, toughness, thermal stability, ductility, etc. Although exhaustive studies have helped understand the thermodynamic basis for the phase diagram of multi-component blended polymers, often it is the melt processing methodology adopted that governs the final morphology in the product and, in turn, its material properties. The work presented in this thesis deals with examining the morphological changes in polymer blends during the processing cycle. Specifically, when a binary polymer blend consisting of components with a large difference in their softening temperatures is processed, an inversion in the phase continuity occurs if the higher melting component is present at a larger volume fraction. This inversion in the phase continuity was coined as the processing-phase inversion. Although several studies have shown this type of processing induced inversion, a detailed understanding of the mechanism has not been fully revealed. In this thesis, we looked at understanding the influence of the nature of minor and major components, the occurrence of an in-situ reaction, and the addition of an inorganic nanofiller on the processing-phase inversion. Microscopic techniques, such as SEM or optical imaging, have been primarily used to characterize the different morphologies that occur during the inversion. In this thesis, we analyze the torque monitored during the mixing along with the recorded melt temperature to independently determine the region of inversion, apart from morphological imaging.
Polymer blends, morphology, polypropylene, Visualization
Ramakrishnan, S. (2024). Unexplored dimensions of processing phase inversion during polymer melt blending (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.