Transition of linear flexible-chain polymers from the fluid to the high-elastic state, spurt effect, and superspurting modes of their motion

Abstract

It is typical of high-molecular linear flexible-chain polymers with a narrow molecular-weight distribution to flow in a broad range of shear stresses similarly to Newtonian liquids. There exists a critical stress at which a spurt effect in the capillary or a jumpwise increase in volume output occurs. It corresponds to the transition of the polymers from the fluid into the rubbery (high-elastic) state. Under supercritical conditions the polymers break at the entrance to the capillary with the result that flowing through the latter is a stream formed by the polymers torn into pieces. For the first time, the regularities of supercritical motion of flexible chain linear polymers have been established.