ISSN:
0032-3888
Schlagwort(e):
Chemistry
;
Chemical Engineering
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
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.
Zusätzliches Material:
16 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pen.760060110
