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Efficient mixing of polymer blends of extreme viscosity ratio: Elimination of phase inversion via solid‐state shear pulverization
Author(s) -
Furgiuele Naomi,
Lebovitz Andrew H.,
Khait Klementina,
Torkelson John M.
Publication year - 2000
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.11274
Subject(s) - materials science , polystyrene , polymer blend , polymer , phase inversion , mixing (physics) , viscosity , phase (matter) , composite material , chemical engineering , thermodynamics , polymer chemistry , chemistry , organic chemistry , copolymer , biochemistry , physics , quantum mechanics , membrane , engineering
A novel, continuous process, solid‐state shear pulverization (S 3 P), efficiently mixes blends with different component viscosities. Melt mixing immiscible polymers or like polymers of different molecular weight often requires long processing times. With a batch, intensive melt mixer, a polyethylene (PE)/polystyrene (PS) blend with a viscosity ratio (low to high) of 0.019 required up to 35 min to undergo phase inversion. Phase inversion is associated with a morphological change in which the majority component, the high‐viscosity material in these blends, transforms from the dispersed to the matrix phase, and may be quantified by a change from low to high mixing torque. In contrast, such blends subjected to short‐residence‐time (∼3 min) S 3 P yielded a morphology with a PS matrix and a PE dispersed phase with phase diameters ≤ 1 μm. Thus, S 3 P directly produces matrix and dispersed phases like those obtained after phase inversion during a melt‐mixing process. This assertion is supported by the similarity in the near‐plateaus in torque obtained in the melt mixer at short times with the pulverized blend and at long times with the non‐pulverized blend. The utility of S 3 P to overcome problems associated with melt mixing like polymers of extreme viscosity ratio is also shown.