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Formation of dispersed phase in incompatible polymer blends: Interfacial and rheological effects
Author(s) -
Wu Souheng
Publication year - 1987
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760270506
Subject(s) - materials science , surface tension , viscosity , rheology , drop (telecommunication) , composite material , polymer , extrusion , phase (matter) , shear rate , reduced viscosity , polymer blend , polymer chemistry , thermodynamics , organic chemistry , copolymer , chemistry , telecommunications , physics , computer science
The formation of dispersed phase in blends of incompatible polymers during melt extrusion with a co‐rotating twin screw extruder was studied, using nylon and polyester as the matrix and ethylene‐propylene rubbers as the dispersed phase. A master curve is obtained, i.e., G η m α/γ = 4 p ±0.84 , where G is the shear rate, γ the particle diameter, η the interfacial tension, η m the matrix viscosity, η d the dispersed‐drop viscosity, and p = η d /η m . The plus (+) sign applies for p > 1, and the minus (−) sign for p < 1. Thus, the dispersed‐drop size is directly proportional to the interfacial tension and the ±0.84 power of viscosity ratio. The dispersed drops are the smaller, when the interfacial tension is the lower and the viscosity ratio is the closer to unity. The interfacial tension is largely controlled by the polarities of the two phases, and can be varied over several orders of magnitude by using appropriate dispersants.