Heterogeneous Blends of Polymers. Rheology and Morphology

Abstract

A single polymer pair (BR and EPDM) was used to confirm experimentally rheology-morphology relationships that have been previously gleaned from comparison of a variety of blend systems. The relative importance of the primary factors which govern blend morphology (composition and relative mixing viscosity of the components) was determined over the range of practical interest. In addition, correlation of mixing rheology with more accurate and complete shear modulus data allowed (a) molecular interpretation of rheological behavior in terms of network parameters, such as physical entanglements, and (b) estimation of the elastic and loss components of the shear modulus during mixing. An attempt was made at explaining the dependence of blend morphology on the viscoelastic properties of the components in terms of a fracture or tearing mechanism.

Phase inversion and co-continuity domain in immiscible polyethylene/polystyrene blends

“…Most of them are considering the viscosity ratio. The first one to appear comes from Avgeropoulos's observations [3]: the phase inversion point is obtained when the torque ratio in an internal mixer equals to the composition ratio. Paul and Barlow [4] have used this result to develop a model based on the viscosity ratio as shown in the following equation:…”

“…Using again Avgeropoulos's observations [3], Ho et al [6] have proposed a new relation based on experimental results:…”

“…Full continuity appears when the entire component becomes part of a single percolating structure. In the last years, many models based on the viscosity ratio of the polymers have been developed to describe the phase inversion process [3][4][5][6][7][8]. More recently, authors have developed new models considering interfacial tension [9] or elasticity [10].…”

Self-healing properties of carbon nanotube filled natural rubber/bromobutyl rubber blends

“…The change in the blend morhology from an island-matrix structure to a co-continuous structure is related to the change of the BIIR/NR viscosity ratio. According to [40,41] the morphology of a binary polymer blend can be predicted by taking into consideration the factor ψ, which is calculated by the viscosity ratio and the volume ratio given in Equation (7). If ψ approachs unity, a co-continuous phase is expected ( Figure 5).…”

Electron-induced reactive processing of thermoplastic vulcanizate based on polypropylene and ethylene propylene diene terpolymer rubber

“…This variation in the morphologies of the two different TPVs was responsible for the different mechanical properties. The morphology of the immiscible elastomer/thermoplastic blends after the dynamic vulcanization process mainly depends on the viscosity and the composition ratio [21][22][23] of the two blend components ( Figure 14). Figure 15 shows the variation of the apparent shear viscosity with the apparent shear rate for virgin PP and EPDM, as well as for the melts mixed for 14 and 10 min, respectively.…”