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Measurement of the residual mechanical properties of crazed polycarbonate. II: Design of experiments analysis
Author(s) -
Clay Stephen B.,
Kander Ronald G.
Publication year - 2002
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.10940
Subject(s) - crazing , polycarbonate , materials science , ductility (earth science) , composite material , strain rate , stress (linguistics) , yield (engineering) , polymer , creep , linguistics , philosophy
The Design of Experiments (DOE) approach was used to build quantitative empirical models of the residual mechanical properties of crazed polycarbonate as functions of relative craze density, crazing stress, and strain rate. Crazing did not affect the yielding behavior of polycarbonate, but increasing the strain rate increased the yield stress according to the Eyring theory. The Eyring activation volume for yielding of crazed polycarbonate was measured to fall between reported values for conformational changes of a dilute solution of polycarbonate chains and yielding of uncrazed polycarbonate. Also, with as little as 1% relative craze density, the failure stress was approximately 10% lower and the ductility was, on the average, 50% lower than for uncrazed polycarbonate properties. It was also found that increasing the crazing stress from 40 to 45 MPa increased the failure stress and ductility for a given magnitude of relative craze density.