ISSN:
0021-8995
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
Fiber melt spinning of poly(ethylene terephthalate) (PET) was studied via modification of threadline dynamics. Several techniques were implemented in the high-speed spinning process for the judicious control of threadline dynamics. This included a thermal conditioning zone (TCZ) for controlling the threadline temperature profile and a dydraulic drag bath (HDB) for controlling the threadline spinning stress. Through controlled threadline dynamics, key factors affecting the structure development - namely, temperature, tensile stress, and crystallization time - were manipulated to favor formation of a highly oriented and transversely uniform structure in the spun fibers. This carries the implication that optimum or near-optimum processing conditions are being applied during the structure development period. More specifically, tensile stress in the threadline, independent of temperature, is substantially increased to many orders higher than that ordinarily attained in the normal high-speed spinning process. Concurrently, the temperature crucial to the structure development is being independently optimized and its duration extended to attain a highly oriented structural order. Properties of the spun fibers were found to be correlated with the threadline parameters including cooling profile, tension profile, and strain rate. PET fibers spun via the one-step process with the introduction of the TCZ and HDB possess superior mechanical performance. Structural characterization suggests that the spun fibers have a high amorphous orientation factor and a uniform radial structure distribution. Further on-line studies indicate that structure development in the threadline is completely different from that of the traditional high-speed spinning process. The attenuation profile of the threadline is observed to be dependent of TCZ temperature, residence time in the HDB, temperature of the HDB, and take-up speed. It is believed that for the melt spinning process with the TCZ and the HDB, the threadline dynamics is changed from one controlled by inertia and air drag forces to one controlled by the imposed hydraulic drag.
Zusätzliches Material:
26 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/app.1992.070460320
