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Biaxial orientation behavior of polystyrene: Orientation and properties
Author(s) -
Zhang Xiaomin,
Ajji Abdellah
Publication year - 2003
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.12268
Subject(s) - materials science , composite material , ultimate tensile strength , elongation , birefringence , shrinkage , polystyrene , toughness , extrusion , stress (linguistics) , transverse plane , polymer , optics , structural engineering , linguistics , philosophy , physics , engineering
Square sheets of extrusion grade polystyrene (PS) were biaxially stretched using a laboratory biaxial stretcher. The effects of process parameters such as stretch ratio, drawing sequence, drawing speed, and temperature were studied. Birefringence, mechanical properties, and thermal shrinkage of the stretched sheets were the focus of this study. A high orientation was achieved at high stretch ratio, and orientations from uniaxial to equi‐biaxial were obtained by controlling the relative magnitude of stretch ratio in machine (MD) and transverse (TD) directions. Stretching increased tensile strength and elongation at break significantly, which indicated an improvement in the toughness of the oriented PS sheets. Those properties were correlated with biaxial orientation factors: a rapid increase was observed for both tensile strength and elongation at break for birefringence levels above −0.005, and below, a plateau was observed. The shrinkage strain and stress were found to correlate well with the biaxial orientation factors. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 487–496, 2003