Abstract
AbstractAn 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.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call