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Viscoelasticity of some engineering plastics analyzed with the modified stress‐optical rule
Author(s) -
Hwang Eui Jeong,
Inoue Tadashi,
Osaki Kunihiro
Publication year - 1994
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.760340210
Subject(s) - materials science , polycarbonate , polymer , polystyrene , glass transition , viscoelasticity , modulus , natural rubber , composite material , stress (linguistics) , dynamic mechanical analysis , polysulfone , polymer chemistry , linguistics , philosophy
The complex Young's modulus, E *(ω), and the complex strain‐optical coefficient, O *(ω), of poly(ether sulfone) (PES), polysulfone (PSF), and polyethermide (PEI), were measured over the frequency range 1 to 130 Hz. The data were analyzed with a modified stress‐optical rule: The Young's modulus was decomposed into two complex functions, E G * (ω) and E R * (ω); the modified stress‐optical coefficient, C R and C G , associated with the rubber ( R ) and glass ( G ) components, respectively, were determined. The results for six polymers, including polystyrene, poly(α‐methyl styrene), and bisphenol A polycarbonate were compared with each other. One of the coefficients, C R , equivalent to the stress‐optical coefficient in melts, mainly depended on the way in which phenyl groups were connected to the chain. The other, C G , was in the range of 20 to 40 Brewsters, and did not strongly depend on the details of polymer structure. The component function, E G * (ω), which was located in the glassy region and originated from the high glassy modulus, was almost the same in shape when plotted against ω with double logarithmic scales. The R component, E R * (ω), located at the long time end of the glass‐to‐rubber transition zone, was slightly sensitive to the molecular structure of polymers.