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Phase transitions during shear flow of two phase polymer blends. II. Styrene‐acrylonitrile/poly(methylmethacrylate) transition to “Homogeneous” melt state
Author(s) -
LyngaaeJørgensen J.,
Søndergaard K.
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.760270508
Subject(s) - materials science , acrylonitrile butadiene styrene , rheometer , composite material , polymer , glass transition , copolymer , phase (matter) , amorphous solid , rheology , crystallography , organic chemistry , chemistry
An advanced hypothesis derived in Part I (this issue) is tested with selected model blends. Blends of copolymers of styrene and acrylonitrile (SAN) and poly(methylmethacrylate), (PMMA) were studied because they are both amorphous, thermally stable, have large density differences, are easy to cut (in an ultramicrotome) and because comprehensive studies have been reported In the literature on this system. The melt viscosity of the blends were studied using a Rheometrics Mechanical Spectrometer and an Instron capillary rheometer. Light scattering measurements were performed during flow in order to measure the critical transition stress. The phase structure of quenched samples was studied by transmission electron microscopy on ultramicrotome cuts. It was shown that an Interpenetrating co‐continuous structure develops when flow is stopped, if a homogeneous phase Is formed during flow. Melt fracture limits the applicability of this approach to nearly compatible blends.