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The use of birefringence for predicting the stiffness of injection molded polycarbonate discs
Author(s) -
Neves N. M.,
Pouzada A. S.,
Voerman J. H. D.,
Powell P. C.
Publication year - 1998
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.10347
Subject(s) - materials science , polycarbonate , birefringence , composite material , finite element method , stiffness , flexural rigidity , mold , flexural strength , flatness (cosmology) , molding (decorative) , three point flexural test , optics , structural engineering , physics , cosmology , quantum mechanics , engineering
Polycarbonate discs were injection molded with different sets of molding conditions. The parameters studied were the flow rate, melt‐ and mold‐temperature. The discs were subjected to three point support flexural tests. Those tests are specially intended for injection molded discs because of their inherent non‐flatness. The through‐thickness molecular orientation was assessed by birefringence measurements along and across the flow direction using the wedge method. This method is ideal to measure the birefringence of materials that are difficult to cut with a microtome. The through‐thickness stiffness of the discs was calculated from the measured birefringence distributions. A composite model of the disc was used in the Algor finite element method (FEM) package to simulate the flexural tests.