The rheological behavior of immiscible polymer blends

Abstract

The complex shear modulus of immiscible polymer blends was measured by a frequency sweep experiment for polystyrene (PS)/low density polyethylene (LDPE) and poly(methylmethacrylate) (PMMA)/LDPE blends at constant composition (13.5/86.5 vol %) and compared with the prediction model of Palierne. Different morphologies of each blend were also prepared using a rheometer with a constant shear rate and different strain. There was morphological dependency on the complex shear modulus at constant temperature. However, this dependency disappeared at specific temperatures in the frequency sweep ex-periment. There seemed to be a specific temperature like critical flow temperature (T cf ) of amorphous polymer. The difference in morphology affected the complex shear modulus of blends below the specific temperature, T cf , but did play a major role in determining the complex shear modulus of blends at over specific temperature. A new method may be needed to determine the critical flow temperature of an amorphous polymer via the measurement of a complex shear modulus for immiscible polymer blends.

Critical length scales for the deformation of amorphous metals containing nanocrystals

“…Systematic variation of the inclusion diameter and the shear band thickness reveals a crossover in length scales that separates distinct plastic flow mechanisms in and around the nanocrystalline inclusion. When considered relative to the shear band thickness, small inclusions deform via heterogeneous, interface-dominated mechanisms, while large inclusions yield via the homogeneous nucleation of dislocations in the nanocrystal interior; nanocrystals roughly twice as large as the shear band width are required for the strongest interaction.The mechanisms and mechanics of deformation in amorphous materials have been the subject of extensive investigation by both experiment and simulation (see, for example, [1][2][3][4][5][6][7][8][9][10][11][12]). The process of shear localization is of particular interest in this regard, as shear banding is often the dominant means of plastic strain accommodation in amorphous solids and, therefore, governs the macroscopic mechanical response.…”

“…The mechanisms and mechanics of deformation in amorphous materials have been the subject of extensive investigation by both experiment and simulation (see, for example, [1][2][3][4][5][6][7][8][9][10][11][12]). The process of shear localization is of particular interest in this regard, as shear banding is often the dominant means of plastic strain accommodation in amorphous solids and, therefore, governs the macroscopic mechanical response.…”

Melt rheology of HDPE/EVA blends: The effects of blend ratio, compatibilization, and dynamic vulcanization

“…However, in the case of polymer blends, the flow behavior becomes much more complex, and to a great extent, it is influenced by other factors such as miscibility, morphology, and interfacial adhesion of the system. Several attempts have been made so far to predict the complicated rheological behavior of polymer blends [1][2][3][4][5][6][7][8][9][10]. Utracki and Sammut [4] made a rheological evaluation of polystyrene/polyethylene (PS/PE) blends.…”