Influence of electron beam irradiation on the microrheology of incompatible polymer blends: Thread break‐up and coalescence

Abstract

SynopsisThe microrheology of polymer blends as influenced by crosslinks induced in the dispersed phase via electron beam irradiation, is systematically investigated for the model system polystyrene/low density polyethylene (PWLDPE).Both break-up of threads and coalescence of particles are delayed to a large extent, but are not inhibited completely and occur faster than would be expected for a nonirradiated material with a comparable viscosity. Small amplitude, dynamic rheological measurements indicated that in the irradiated materials a yield stress could exist. In contrast, direct microrheological measurements showed that this yield stress, which would prevent both break-up and coalescence, could not be realized by EB irradiation. Apparently, the direct study of the microrheology of a blend system is important for the prediction of the development of its morphology and it is not possible to rely only on rheological data obtained via other methods.

Coarsening of immiscible co‐continuous blends during quiescent annealing

“…Static coalescence for dispersed phase/matrix systems (Fortelný and Zivny, 1995a; Yu et al, 2000; Van Gisbergen and Meijer, 1991) has been studied by a number of laboratories. Fortelný and Zivny (1995a) proposed a theory to describe coalescence in polymer blends with a high content of the dispersed phase.…”

“…Another coalescence model developed by Yu et al (2000) also suggests a similar four‐step coalescence process. Unlike other mechanisms that took the film draining time as the coalescence time (Fortelný and Zivny, 1995a; Van Gisbergen and Meijer, 1991), Yu et al (2000) also took the merging time into account and considers it as the dominant process for a high viscosity system. They obtained a relation of particle size growth as R ∼ kt α , where the constant k is related to the volume fraction, interfacial tension, and the zero‐shear viscosity of dispersed and matrix phase.…”

Surface Modification Strategies for Multicomponent Polymer Systems. 2. Study of the Interfacial Tension and Morphology of Linear Low-Density Polyethylene/Poly(vinyl chloride) Blends

“…It is limited to systems that have no yield stress at low shear rates. Until now, it has been used in some immiscible and compatibilized polymer blend systems (Chappelear, 1964;Chapleau et al, 1995;Elemans et al, 1990;Elmendorp, 1986;Lepers and Favis, 1995;Luciani et al, 1996;Mekhilef et al, 1997;Van Gisbergen and Meijer, 1990;Watkins and Hobbs, 1993). To our knowledge, however, no data concerning the interfacial tension between linear low-density polyethylene (LLDPE) and poly(vinyl chloride) (PVC) melts measured has been reported in the literature.…”

The supermolecular structure of isotactic polypropylene/atactic polystyrene blends

“…A step required for coalescence is the deformation of droplets during collision along with the removal of the matrix film in between the droplets. This step is often considered as the rate‐determining step for coalescence [67, 68], and has been related to interface mobility and size of the droplets. For blends such as iPP/PS blends, the final particle size increases with the dispersed phase concentration due to increased coalescence [15].…”