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Interaction of process variables with the fracture behavior of amorphous polystyrene during attrition
Author(s) -
Kubisiak Michael P.,
Quesnel David J.
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.10622
Subject(s) - materials science , extrusion , composite material , comminution , polystyrene , shrinkage , transverse plane , fracture (geology) , microstructure , expansion ratio , polymer , metallurgy , structural engineering , engineering
This study investigates the fracture of oriented general‐purpose polystyrene. Specimen microstructure was controlled using an extrusion‐sheeting technique where draw ratio, polymer melt temperature, cooling roll temperature, and nip roll pressure changed according to a designed experiment. Sharp‐notched tension results display a 4X difference in longitudinal vs. transverse specimen values. Shrinkage measurements show contraction in the machine direction amplifies with increasing draw ratio. Craze formation is visible only in those specimens tested in the longitudinal direction. Fracture mechanisms have strong orientation dependence and the extrusion‐sheeting process produces an ideal system to study the effect on attrition. Comminution studies illustrate draw ratio has an effect on the final median particle size and width distribution of the powder. Increasing the draw ratio reduces the volume median particle size and minimizes the formation of fine particles. A monotonic fracture mechanism was initially considered but rejected in favor of a low cycle fatigue model based on estimates of fracture strength.