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Melt viscosity and flow birefringence of polycarbonate
Author(s) -
Nagai Tohru,
Kimizuka Yuichi,
Nito Keiichi,
Seto Jun'Etsu
Publication year - 1992
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.1992.070440706
Subject(s) - polycarbonate , flow birefringence , materials science , birefringence , anisotropy , composite material , viscosity , polymer chemistry , optics , polymer , physics
Melt viscosity and flow birefringence of bisphenol A‐type polycarbonate were measured and analyzed by the application of rubber‐like photoelastic theory. The melt viscosity in the Newtonian flow region increased with the molecular weight to the power of 3.4. In polycarbonate, the shear stress of the Newtonian flow region was to 10 6 dyn/cm 2 , whereas in PMMA it was at most 3 = 10 5 dyn/cm 2 . The flow birefringence δn has a linear relation with shear stress S , that is δn = 5.7 × 10 −10 S . The principal polarization difference of flow unit α 1 – α 2 was 1.62 × 10 −23 cm 3 , which was obtained by the application of the rubber‐like elastic theory. In PMMA, it was 3.9 = 10 −25 cm 3 ; about 1/40 of that was polycarbonate. The anisotropy of polarizability of the flow unit of polycarbonate was also about 40 times larger than that of PMMA. So the anisotropy reflected the large flow birefringence of the polycarbonate.