Palieme emulsion model

Paheme emulsion model failed to describe the dynamic modulus of the PP/EPDM blends after radiation, because the viscosity ratio increased significantly and the rubber phase changed from deformed droplets to hard domains after radiation (Cao et al. 2007). Intercoimections among inclusions of the dispersed phase (Shi et al. 2006) and the existence of multiple emulsion (emulsion-in-emulsion) structure exhibiting different relaxation domains in compatibilized systems are other factors contributing to the failure of Palieme s model (Friedrich and Antonov 2007 Pal 2007). 

Fang et al. (2005) studied the thermal and rheological properties of two types of m-LLDPEs, two LDPEs, and their blends. The C2+6 m-LLDPE-1 was immiscible, whereas the C2+8 m-LLDPE-2 was miscible with the LDPEs, indicating that increasing the length of SCB in m-LLDPEs promoted miscibility with LDPE. The Palieme (1990, 1991) emulsion model provided good predictions of the linear viscoelastic behavior for both miscible and immiscible blends. The low-frequency data showed an influence of the interfacial tension on the elastic modulus of the blends for the immiscible blends. 

Structure and properties for binary blends of PLA and PBS are studied both in the solid and molten states. It is foimd that PLA and PBS are immiscible in the molten state and the blends exhibit phase-separated structure. The interfacial tension between PLA and PBS is estimated using a rheological emulsion model proposed by Palieme and foimd to be 3.5 mN/m as shown in Figs. 4.29,4.30 and 4.31. Basic theological parameters are also evaluated for PLA and PBS. It is suggested that the entanglement molecular weight of PLA is lower than that of PBS. 

For such blends containing the droplets embedded in matrices, linear viscoelastic moduli can be calculated from several models formulated on the basis of the local stress balance (or other phenomenological criteria). " Among these models, the emulsion model proposed by Palieme appears to be most frequently compared with the experimental data. The complex modulus G =G + iG" deduced from this model can be summarized as ... 

Oldroy s model was extended by Palieme (1990) to emulsions with polydisperse spherical drops. The model considered viscoelastic liquids, the concentration range was extended up to that at which drop-drop interactions start complicating the flow field. However, the drops must be spherical, undergoing small deformation, and the interfacial tension coefficient was considered constant, independent of stress and the interfacial area. The following relation was derived for the complex modulus ... 

The model due to Palieme accounts for the viscoelastic nature of the component phases and the particle size distribution in non-dilute emulsions [91]. The complex shear modulus of the blend can be expressed in terms of the complex moduli of each phase, the interfacial tension, and the radii of the dispersed droplets... 

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