Premium
Influence of melt deformation history on orientation in vitrified polymers
Author(s) -
Oda Kunio,
White James L.,
Clark Edward S.
Publication year - 1978
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.760180111
Subject(s) - materials science , birefringence , isothermal process , polystyrene , composite material , shear flow , polymer , deformation (meteorology) , shear (geology) , shear stress , flow birefringence , stress (linguistics) , flow (mathematics) , critical resolved shear stress , spinning , shear rate , mechanics , thermodynamics , optics , viscosity , linguistics , philosophy , physics
An experimental study of the development of orientation in polystyrene melts during flow and its retention in vitrified parts is described. It is shown on the basis of elongational and shear flow experiments that orientation in vitrified polystyrenes may be predicted from a knowledge of the stress field at the time of vitrification and application of stress‐optical laws. More generally a relationship between birefringence and principal stress difference is found which correlates (1) on‐line isothermal shear flow, (2) on‐line non‐isothermal elongational flow (melt spinning), and (3) vitrified samples formed in both shear and elongational flow. It is further proposed that orientation in polymer chains in deforming melts is uniquely dependent on stress—specifically, that the ratio of the stress‐optical constant C to the intrinsic birefringence Δ° is approximately a constant.