Premium
The phenomenon of draw resonance in polmeric melts. Part II—correlation to molecular parameters
Author(s) -
Bergonzoni A.,
DiCresce A. J.
Publication year - 1966
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.760060110
Subject(s) - materials science , rheometer , composite material , piston (optics) , extrusion , fiber , amplitude , viscosity , resonance (particle physics) , swell , mechanics , rheology , thermodynamics , optics , physics , particle physics , wavefront
Abstract The Phenomenon of draw resonance and the cyclic size fluctuation of an extruded shpae are related to basic changes in the “melt strength” (force per average cross‐sectional area required to draw the molten fiber down under fixed conditions). Melt strength values are obtained by a modified rheometer which consists of a vertical chamber to melt and hold the polymers at 190–250°C, a piston for extrusion, a take‐up system, a strain gauge to measure the drawdown force and a recorder for continuous force‐time plots. Melt strength increases with take‐off speed but not proportionally. At higher velocities, draw resonance is apparent through a sinusoidal‐like variation in fiber diameter. The amplitudes of melt strength and diameter waves are correlated with molecular weight, melt viscosity, swell, melt temperature and take‐off speeds.