Premium
The development of flow instabilities during the injection molding of multicomponent resins
Author(s) -
Hobbs S. Y.
Publication year - 1996
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.10543
Subject(s) - materials science , polycarbonate , composite material , gloss (optics) , surface roughness , molding (decorative) , acrylonitrile butadiene styrene , surface finish , scanning electron microscope , optical microscope , rheology , coating
In this study, several blends of BPA polycarbonate and acrylonitrile/butadiene/styrene (ABS) resins having different gloss levels and microscopic surface roughness values were injection molded over a range of injection rates. Changes in surface appearance were monitored by visual observation, optical microscopy, and electron microscopy. The onset of unstable flow was marked by the development of regularly spaced surface patches on the molded parts. The surface irregularities were found to be strikingly similar to those produced by dragging crosslinked rubbers across hard surfaces. It was observed that blends having higher surface roughness values had lower coefficients of friction and exhibited unstable flow at lower stresses than compositions with smoother surfaces. The data were used to quantify the rheological parameters and surface characteristics defining an acceptable molding envelope for these materials.